It was standards based, but the way Apple ran the launch and marketing (kind of genius, actually), they gave the impression that Apple Pay was the only phone-based tap-to-pay around. Merchants would have signs saying "Apple Pay accepted" but not mention Google, leading to confusion over whether non-Apple payments would work.

Part of that is definitely the confusing state of payments on Android. Samsung Pay could refer to either NFC or magstripe-emulation. Google, of course, is terrible at branding stuff, and between Wallet and the many iterations of Google Pay it's still difficult to figure out what's what.