After the monthly payment the ledger is swept clean (or at least that happened on my install). In my case the payments went totally wrong (see: Payments going wrong, as in not going to the visited sites).
In order for people to dispute payments they will need to be able to proof that something went wrong, or to check if their memory of visited (and in- or excluded sites) is correct. If there is no dispute and control mechanism people (and government agencies) will be or can become distrustful.
It also gives you the opportunity to check what, if anything, went wrong. Of course this might run afoul of the reason why most people will want Brave: privacy. But sometimes you have to trust your supplier with some private information in order to solve a monetary problem
I for one would not mind sharing more information with you than you would be able to see if that improves the Brave browser and services.