Facebook adverts are not only way of advertising, don't forget there are other ways too. Even if Facebook bans ad's of crypto forever, it is not end of the world. Good projects will come out on day light just the same. Maybe a bit slower, but they won't be stopped by Facebook. Those that are stopped by it, maybe they didn't deserve to be known. Good projects with good reputation will come out sooner or later.
But, do not forget that in Facebook to find a large number of users, this is a worldwide network, when compared with other social networks