Cheat detected

I just played a game and after the game there was a Cheat detected massege next to White win.

I did not cheat, what happened?

They cheated, so you won.

More specifically it means that your opponent pulled up the position in Lichess' analysis board to cheat, and lichess' cheat detection system forfeited the game, giving you the win.

what grace has to gain by cheating ?? I see no sense in that.