Subscription models only make sense for an app/service that have recurring costs. In the case of Lemmy apps, the instances are the ones with recurring hosting costs, not the apps.
If an app doesn’t have recurring hosting costs, it only makes sense to have one up front payment and then maybe in app purchases to pay for new features going forward
several people have confirmed it… I haven’t seen them explain how exactly, but they seem convinced it is causing crashes so they blocked it. Lemmy is practically in the realm of voodoo PostgreSQL at this point. Since April or May it’s been scaling very poorly as data gets added.