I have a somewhat peculiar use case where the Apple Pay button may need to be shown when it is technically usable, but application validation would disallow it's usage.
Apple Pay is meant to be for instant purchases. In my case, a user may select the Apple Pay option, and then after the fact try and change the date of payment to some future date. We would throw an alert if the button was tapped to disallow an attempt at payment if the wrong date is selected.
It seems like this behavior would go against:
1. Do not use the Apple Pay payment button to invoke other views.
2. The payment button must always invoke the Apple Pay payment sheet.
3. Don’t display any Apple Pay UI if a user can’t use Apple Pay.
# 3 seems like the big one here.
