I do see your point but in this case _everyone_ pays the 5% even though the payout only happens once per project and the payment also only happens once per person donating.

It might be that it is this expensive to run, I don't know. It just seems unfair to me that the platform would get 5% and "only" 95% are distributed to the projects. I do understand that everyone has a different definition of "fair" and I also don't know what I'd be willing to spend. It's something I'd need to think about.