This is a great idea categoriaopueta. I´m 100% with you.
Play against computer in variants
To put things in perspective: Having the self-learning network (LeelaZero) learn normal Chess took more than 6 months by a collaboration of some 100 volunteers donating the use of their computer to the project. Making a given engine available for on-line play might take a week of programming by a single person, at most.
Of course there already exist many engines that play variants. Even a Stockfish version. And I don't know exactly which variants they offer here, but chances are Fairy-Stockfish already plays several of those.

Great insight HGMuller! I didn't know about Fairy-Stockfish, went through the repo, looks like it would do the job for this case, i.e. I don't think a super AI that can beat the best humans would be necessary here at all, just a decent engine to play against when there are no human players available.
Is there a part of the forum for feature requests/suggestions? Can't seem to find that, and I'd like to see if something was discussed already along these lines - one week for one dev doesn't sound too much work for this.

Ah, missed the search in the forum page. Found one small discussion
https://www.chess.com/forum/view/site-feedback/feature-request-bots-for-variants
will go through the rest and comment there.
I know this is not a trivial feature to develop, but I'm interested in knowing if other people think this is a good idea too (or if this has been discussed already).
I think this is particularly good for variants like bughouse where it is difficult to find other teams to play against at certain times of the day/week, or 4 player chess.
I'm thinking that nowadays with these self-learning neural networks, training the AI might not be such a headache (though not trivial). Building the services would def take some work, and might not pay off for the website though...
thoughts?