You can turn these off. It’s part of their crypto rewards system (you get occasional ads, some crypto and then some of it gets distributed back to the websites you vist most, or just the ones you select) so it’s on by default. But you can easily opt out of this from settings.
I don’t think this whole crypto system lifted off really, but it was a neat idea to reward web content creators and users, according to traffic and preferences.
Lol, thanks for helping convince all my relatives and friends to finally leave Facebook then, Facebook. Couldn’t think of a better incentive myself.