I feel it's the contrary. We are generally happy to refund customers that are not happy with our service, but the app store is the only payment system where we cannot refund them (I don't really know what the UX looks like on the customer side, but I think they have to contact Apple to ask for the refund and it's not always as easy as it should to get the refund)
Note that things might have changed since I worked on this stuff.