Apple is doing a lot with e-commerce... Especially NFC -- they just killed it with iBeacons.
The use of the PrimeSense technology, as I described it, has to do with securing/identifying an external device like an iPad cash register with the secure (TouchID) data on your device... "It takes two to tango" securely.
I suspect I understand it as well as you do!
I have been purchasing Apple devices since 1978 (Apple ][). I have been observing/working with Apple since 1978 as: costumer; user; dealer/reseller; supplier; co-developer on a project •; OSX Developer; iOS Developer.
* This was a Point-Of-Sale replacement for the cash register for Apple Dealers using the Mac and LaserWriter.
I suspect I understand what motivates people to buy Apple. In my 11 years as a Computer dealer (including Apple) we had international customers such as Daimler/Benz, EMI Thorne, Schlumberger/Fairchild, Intel, National Semi, IBM, Apple, Xerox, HP...
Our household of 2 adults and 3 teenagers is all Apple currently we use: 3 iMacs; 3 Mac Minis; an AluBook 17", 3 AppleTVs; 2 Airport Express routers; iPhone 5S, iPhone 5C, iPhone 5; iPhone 4S (2); iPad 4; iPad 3; iPad Mini; iPad 2 (2)... a bunch of older iPhones aPads and iPods...
Yeah, so... As I stated, the technology, certainly, has applications in games and TV...
That doesn't preclude the use of the same [or a variant of the] technology for ecommerce. Tim Cook has business training, and a business background. I am sure he is aware of the business potential of this technology. The purchase of WiFiSLAM supports this as it is aimed at indoor location and navigation -- much applicability to business/ecommerce -- little to TV or gaming UEX.
It has applications in all 3D Modeling environments applied to Engineering fields in static and dynamic loads, etc, Aerospace, etc. The limiting factor [and necessary one] is where to start and build a broad and deep foundation of markets from Consumer to Enterprise, and public sector markets.