A fundamental flaw in this, is it still involves user data, even if “anonymized”. You can advertise without any user data. We do it all the time. Does a television channel know your gender? Does a radio station know if you bought a car recently? Does the newspaper know your hobbies?

At least it appears to be something that gets triggered. In theory, if a node is not under attack or heavy usage, this isn’t a consideration. Doesn’t seem to be a perfect solution as it still slows the traffic of legitimate users in the event of an attack. I don’t know the full details, but in the worse case it makes it easier to semi-DoS, maybe not by fully making a node unresponsive, but by making the service so painfully slow that users may give up on it.