Correspondence chess.

i agree. Not only will it just be engine vs engine, but it is an outdated, outmoded idea

I like the idea of correspondence chess (I used to play at gameknot.com), but it shouldn't count for the normal lichess.org rating (maybe only a seperate rating or only casual games) because it is way too easy and common to cheat in correspondence chess. If it doesn't count for the normal rating then you can still play against opponents who are as good as you are whether any of you is using computer assistance or not. In normal games I often analyze the game with my opponent and it would be great if we could play the same game again, but with more time so we can find out where we made mistakes (first without engines because you can learn more that way and then with engines so we can find out if our analysis was correct).

I used to play CC. On gameknot, redhotpawn, chesshere and chessworld(?).

Honestly though I dont really want Lichess to get it,
as it will split the user base.
Its also harder to find cheaters.

I played it over IM once to simulate "blindfolded chess" where I just typed all my chess moves in ASCII text without looking at the board.

Made a couple of illegal moves pointed out to me but finished the game in victory anyway.