That's obviously true globally, but not for some of their more important markets. iOS and Android are roughly equivalent in the US for example, with the latter having maybe 10% more of the market β I think?
While there's no doubt that instant money transfers are particularly useful in less developed markets, it's not like it wouldn't still be a useful service in the US.
"I want to send you money. Do you have an iPhone?" "Yes" "Okay, here's the money."
versus
"Do you have an iPhone?" "No" "Okay, download SquareVenmoPal and I'll send it to you".
There's a built-in audience for Apple Pay that might prove to be beneficial.
[0] - http://www.businessinsider.com/android-is-for-poor-people-ma...
[1] here's a deconstruction of the data in the article: http://forums.appleinsider.com/t/158143/twitter-heat-map-sho...
[2] here's one explanation why: http://readwrite.com/2013/01/29/why-do-americans-hate-androi...