It's not about Apple Pay being shit or not. It's about the fact there is a damn near complete web standard on handling secure pay that Edge, Firefox, Chrome will be using. Then Apple says "yea fuck that standard" and made their own for Safari.
Which means for us developers instead of having to code to one standard that works across all browsers, we have to code to two because Apple. And to make it worse, I'm pretty sure Apple's implementation isn't open license so it can't be rolled into the standard.
To be fair, it wasn't developed for Safari, it was developed for the iPhone. It only makes sense that, at some point, Apple would then move it to their computers. I'm glad this is happening, because the more adoption Apple Pay gets, the more it might convince additional retailers to support it.
And, as someone who has done web development for too many years to count, having to account for standards and then popular-but-not-as-standard things is just part of that world. Then, as a consumer, if you're a site wanting my money, I don't really care about you having to do extra work. I can always just give my money to someone else who's willing to do that.