I think they mean IAP, not Apple Pay. Apple requires every app (unless it's for a physical product and some other exceptions) to use Apple's in app purchase system. You can pay with credit card, gift cards, etc, but 15% (30% over $1mm) goes to Apple, not the merchant - which is what this bill is about, since Apple has a monopoly as the only app store they can charge whatever they want and developers have to put up with it. You can't embed your own payment system, or even make references that such system is available elsewhere (e.g. on your website)
That is very different. Most users like apple's consistent payment flow and protection it provides, especially if you've dealt with other providers online (and all the scam tactics).
I think many customers will switch to alternative payment solution if the price is lower by 30~40%. Consistent payment flow and protection is of course desirable, but I don't think that's worth the current cost. Perhaps 10% makes sense.
