Why would anyone want to do that? Even if it was slightly profitable, the risk and time wasted would seemingly nullify any gains you would receive.
Because some gamblers main priority is accumulating wager or hunt specific high multiplier that needs huge number of trials in able to achieve their target.
I usually use auto bet when I’m competing with wager based tournament or hunting specific multiplier on slot games for contest purposes.
But if you are just playing casually, I believe manual bet is the best option to enjoy the game.