Bots are just used mostly for timed trades or immediate executions when price points hits a certain point that you indicated. It makes monitoring less of a hassle since, well, you don't have to do it all the time. Heck if you're good enough I reckon you can be a full time trader even if you're not looking at charts for most of the day.

As for a bot that self analyzes the market and trades by itself, I'd much rather do copy trading than do something as risky as that. At least in copy trading I can blame someone else! God knows how much shit would go on if such a bot is actually used for trading.