[rexaliquid]

The problem that charging up-front was created to address was people pledging money, reaping rewards, then dropping out before paying any money at all. With this system, if someone signs up for one month, then drops, the creator still gets paid for that month.

Worst case: a patron could game the system and only pay half as much as other patrons for the same content. That would involve pledging and canceling repeatedly every other month. That is not a likely scenario, and still infinitely better than the previous worst case: patrons paying $0 for that premium content.