The only plus side I can see for those already on MPP is that in order to participate, they at least have to pay to become a member....

BTW, if you look on Stripe's countries that are eligible page, some countries still aren't eligible for Stripe, some others that are, still have to jump through one or 2 extra hoops to be able to receive payments.

Besides, if those that are now eligible pony up and pay the monthly membership (now necessary for MPP) and are willing to jump through a few extra hurdles to receive payments from Stripe, then why not?