One problem is the price of bitcoin can be stable for weeks at a time in which case you can't make any money from trading. Then what happens is that the price of bitcoin moves suddenly, but you make nothing because you are asleep. So you do algo trading, and then you end up losing money because of bugs.
Trading with bots can be profitable but you need a good programmer, if you are not one yourself, and then you need to update the bot constantly in order to respond to new strategies that you may devise.
I think he do not have to rely on any bot as a bot is unable to earn money for us on trade we ourself have to do trade and have make decisions for our investment and for choosing the assets for us which a bot is unable to conduct.