That surely depends on your logic. I built my own bots, with different logics (Arbitraging, sentiment analysis, TA, etc), some worked for a while, some didn't, but yes some of the bots made me some profits for a few months
Cool. I have heard about guys, who make different bots and get benefits from them but I never tried it. I agree that auto trading can be a risky thing, but it works well for people, who have a main job and do not have too much time to make pairs and go through long and difficult calculations, technical analysis and whatnot. Bots simply make the work of traders easier.