I don't buy this idea that Wu is donating 100s of dollars to herself for no better reason than to keep her patreon total up. I've never seen Wu give the slightest shit about Patreon, or keeping her patrons happy.
It seems fairly obvious to me that every month a certain percentage of her patrons' credit cards expire and their payment fails. They get a notice from Patreon to update their details, some of them do and some of them take it as a prompt to stop their patronage because it's lost any meaning for them. So at the beginning of every month she gets a large drop in patrons, and she gains a handful back over the course of the next week or so.