There are several reasons why using trading bots is better than manual trades in some occassions :
Trading bot offers a continuous trading 24/7 in which cryptocurrency market is always open without working days. This will help traders screen time a lot since they can automate the trades and leave the screen for longer time.
Emotionless. Trading Bot trades using predefined variable, reducing the risk of phsychological trades or impulsive trades which often leads to FOMO.
More powerful. Trading bots data processing is way higher than traders. Trading bot can easily process piles of data and give a rational conclusion/insight from the data.