You are cruel.
True enough, but I do it so I don't have to get arthritis tapping the same button to cross a long room. I know the enemies are on the other side of the board, for instance, and I just want to get on with clearing a room and get back to what I was doing.
Even if the board is cleared, conceivably you could have trouble: say you're cleaning out the last of the board before going through the elevator. Everything is dead, you've already waded through a big field of acid, and you don't have enough health to get back through it. But when running through the room, just to save time, like the function purports to do, you run smack into a teleporter, which puts you on the other side of that frigging acid field again, making it a numbers game which you will lose because your health is low.
While someone could just say it's some sort of Punish the Weak thing, I think it goes against the general function of autorun, which is to stop before the player would have to make a choice about a thing. You could also punish a player for running by letting it run straight over acid, but I don't think anyone would suggest it.