But Square enjoys a tremendous user experience advantage. It's easier for everyone to use.

Now, in my theoretical universe where Apple is a bunch of dicks and decides that they'll keep the NFC APIs to themselves, and assuming they run a service that competes with Square...

Who's going to want to attach a plastic weiner to their phone versus just having the "magical, it just works" action that Apple will provide with their service?

Of course, it may well be that Apple wants a usurious fee for their service (30%!) and Square could still compete on price. Still – a world where Square can harness NFC directly on an Apple device is a much better deal for them than one where they can't.