Does anybody even use Facebook anymore? (At least among the crypto population)
examplens is obviously using it 
I think that Instagram has the same owners as facebook, and they are known for privacy violations.
Most crypto oriented people this days are probably hanging on twitter and nostr this days.
Seen from the point of view of promotion, I often got better results from FB posts compared to Twitter, at least when it comes to ordinary users, not influencers or big accounts. I am referring to crypto things.
I would not ignore the potential of promotion on social networks, regardless of whether we think that no one uses it.
I think promoting a mixer-related website on Facebook is a bit contradictory. No one seeking privacy would ever search on Facebook...