Good for Apple, this isn't their first green purchase or project and it won't be their last.
Remind me again, when did we last hear about Google/Samsung/Facebook buying something that wasn't just to increase profits.
I can't see Square being a worthwhile investment unless they have some IP that Apple can't find an alternative for and Square wouldn't licence. Considering there are other companies doing the same thing and Square aren't suing, I'm guessing the IP is elsewhere and Square just licence it themselves.
All Apple need to do is package their version of PayPal Here, make it work nicely and they'll be away. If they could do a tie in with PayPal so you could iMoney to a PayPal...