Inside iOS 9.3: Apple's native apps gain new 3D Touch shortcuts on iPhone 6s
The upcoming release of iOS 9.3 will bring new 3D Touch shortcuts to Apple's built-in apps on the iPhone 6s, most notably giving users the ability to quickly update App Store installs, or access battery or Wi-Fi settings.

Developers were issued the first beta of iOS 9.3 this week, revealing some of the changes planned for the forthcoming update. In particular, Apple has added a new "Update All" 3D Touch shortcut to the App Store icon, as well as a "Purchased" link.
Previously, the iOS Settings app lacked any 3D Touch shortcuts at all, but that's set to change with iOS 9.3. In the first beta, developers can quickly access "Bluetooth," "Wi-Fi," "Battery," and "Set Wallpaper" by firmly pressing the icon.

Apple's native Weather app also gains 3D Touch support in iOS 9.3, providing iPhone 6s and iPhone 6s Plus users with quick access to their most frequently checked cities. A link to add a new city is also offered.
The iTunes Store now comes with "View Downloads" and "Purchased" links via 3D Touch, and Apple's Health app icon can be used to quickly access "Show Dashboard" and "Show Medical ID."
Even some of Apple's legacy iOS apps were given a 3D Touch upgrade in the first beta of iOS 9.3, as users can press down on the Compass icon to access "Start Level" and "Start Compass." The native iOS Stocks app also comes with a 3D Touch link to search for stocks.

Developers were issued the first beta of iOS 9.3 this week, revealing some of the changes planned for the forthcoming update. In particular, Apple has added a new "Update All" 3D Touch shortcut to the App Store icon, as well as a "Purchased" link.
Previously, the iOS Settings app lacked any 3D Touch shortcuts at all, but that's set to change with iOS 9.3. In the first beta, developers can quickly access "Bluetooth," "Wi-Fi," "Battery," and "Set Wallpaper" by firmly pressing the icon.

Apple's native Weather app also gains 3D Touch support in iOS 9.3, providing iPhone 6s and iPhone 6s Plus users with quick access to their most frequently checked cities. A link to add a new city is also offered.
The iTunes Store now comes with "View Downloads" and "Purchased" links via 3D Touch, and Apple's Health app icon can be used to quickly access "Show Dashboard" and "Show Medical ID."
Even some of Apple's legacy iOS apps were given a 3D Touch upgrade in the first beta of iOS 9.3, as users can press down on the Compass icon to access "Start Level" and "Start Compass." The native iOS Stocks app also comes with a 3D Touch link to search for stocks.

Comments
I'm looking forward to using these new functions on my 6+. Personally, we earn iTunes gift cards when we use our Barclaycard (via Apple Pay, of course) to purchase Apple products. It would be handy to redeem them via my phone.
3D touch will become more and more relevant the more developers implement it. This is Hours Tracker which I use all the time. 3D touch lets me go directly to the functions I use most often and then get back to work.
So why bloody not shouldn't Apple be the first to implement and promote it?
In designing the force touch interface, you don't look at the four most common functions that people use while they're in the app, for the simple reason that they're not in the app. And in many situations they probably don't really need to launch into the app to get hold of a piece of information or perform a particular function.
In other words, you use real world scenarios: what would a user suddenly need to do from the app grid and where would it make sense to put it. Search is the obvious one, because I can see a case where I'd be walking through a shop, and I hear some piece of music playing in the background. If I know the title or the artist then I can just hold down the iTunes Store button and use the search to find it for me.
At first glance, Redeem seems less obvious to you because Redeem is not one of the top five things you'd do when you're inside the app. But it's certainly one of the top things that you should be able to do without going inside the app. If I'm given an iTunes voucher as a present then the first thing I'd do (after wondering why I didn't get more money) is redeem it before I forget about it or lose it. That's the difference; it's not about the most popular function, it's about the function that makes the most sense to do quickly and without necessarily accessing the full application.
And if you think it through, your argument makes even less sense if you remember that someone has already paid for the voucher and Apple has pocketed the money before it's actually redeemed. It would make more sense from a financial standpoint to leave the Redeem item off the menu altogether.
I'm going to make a prediction: When Apple upgrades the Apple Store app, EasyPay will appear on the 3D touch menu. Why? Because when I'm standing in an Apple Store holding a new gadget I want to buy, then there's no reason why I should have to open the Apple Store app to pay for it. I should be able to just hold down the icon and be allowed to pay directly from the there.
Inside my car, there's a touch screen for doing all sorts of clever things with music and telephones and maps and whatnot. It's probably the set of functions I interact with the most while I'm using the car; oddly enough, even though I use those functions heavily, Toyota didn't feel the need to put the same touch screen on the outside of the car door. It's all a question of context.
So much more useful than a shortcut to toggle "cellular" on or off would be.
And battery!! Now I can pop up a link to check battery status rather than having to look at the upper right corner of my screen!
but if you have data to show thats unlikely, id love to see it.
So it suits your use cases, which you imagine to be "real world scenarios" and is therefore valid?
To me it looks more like an attempt to remind users they can buy cards with credit for themselves and as gifts. And that redemption of these is (in Apple's eyes) the second most important thing you can do. More so than updates, in the case of the AppStore. That's intriguing.
Since you're saying "surely apple has metrics..." and that those metrics favour these choices, aren't your required to show some supporting data?
Like is said: lazy and stupid. Figure it out yourself.
My guess (which is as good as yours) is it's there simply as advertisement to remind people about buying and using (now, with all new the convenient pop-up!), Apple gift cards.
Or two.
The only way I know to redeem a card in the App Store is:
1) Open the App Store app
2) Scroll to the bottom of the page and select Featured (Featured is the default if the App Store isn't already opened in background)
3) Scroll to the very bottom of the page
4) Select Redeem
I redeem gift cards from time to time, but I don't always remember where I found Redeem. Maybe I should invest in Ginkgo Biloba, study flash cards, or applaud Apple for making this easier and a benefit for the both of us.
Redeeming a card in iTunes is a little easier- for 2) you can select Music, Movies, or TV Shows at the bottom of the page. And as mentioned earlier, the voucher has already been paid. It would be to Apple slight advantage if they were, like gym memberships, purchased but seldom used. That Apple put it in the second position means it's a reminder or advertising ploy may be correct. Who cares. Most of us aren't going to spend money because we saw it on a menu. When we are looking for an gift, maybe this works to prompt us to give a card. What a conspiracy!
So you get or give someone a card and and use 3D touch to select Redeem without having to open the app first. That seems like a very practical win-win to me, and a natural for 3D Touch.