Yes but if it was optional, you would have people saying that players SHOULD use it and it could easily cause arguments. Its like the old argument about if a person should resign a game when the outcome is an obvious loss for them, or should they play to the end.
Many people get irate if a person doesn't resign when they'd like them to. It would be the same here, if a person for instance was stuck on the bar in backgammon, but wished to see their opponents moves, they would not use an auto feature.. and their opponent would say 'can't you use it?'... It could cause a lot of tension. IMHO