Apple is placing warnings on EU apps that don't use App Store payments
theverge.com
theverge.com
How could this possibly go wrong?
Typical fees for processing a payment are 2% or less.
Apple charges 30%.
And if they are not?
Charging less can expand the market and lead to increased sales at the expense of your competition.
Avoiding Apples 30% cut gives vendors the opportunity to make their own decision.