I'm not quite sure if it is a bad move.

Well, they are prohibiting Ads about cryptos, that seems to be bad and going against the current trend.
However, as many of this type of "crypto" Ads on Facebook seems a bit weird and fishy (at least for the Ads I have seen on Facebook), I think it may be better for Facebook to temporarily ban them for the sake of maintaining the website's reputation.

I guess it would be the rationale behind all the bans. Hope that when the crypto things are more well known, and the public are more well educated on these sort of things, social medias can actually open their arms and welcome the Ads.