There is no anonymity between the creator and Patreon, or between Patreon and patrons. The anonymity is between the creator and the patrons.
I don't see any reason why this would be illegal, especially as Patreon does this in countless jurisdictions.
> "by works" payment model is illegal. You can receive donations or have subscriptions or pay per view but you cannot "maybe deliver", "deliver maybe one work, maybe ten". Again, illegal as fuck.
This is a model that Patreon already supports (again in countless jurisdictions), so unless their legal counsel is completely incompetent it can hardly be "illegal as fuck".