Games are meant to be played by people but if a person has a limited amount of time to play a game(say 30mins-1hr) that honestly doesn't add up to much. The addition of the OPTION to bot when away means this player who has a life can still complete a bit more than if they were only limited to playing for a short amount of time.
Also the majority of the games that have bots focus more on PvP rather than PvE such as Mu Online where end game means killing players,guild wars,castle siege,etc.
On topic though...
Jade Dynasty has a bot system I believe. The majority of games that are released usually don't have bots nowadays since grinding is reduced greatly. Might I suggest Aura Kingdom? It has easy leveling so you can get quite a bit done with whatever time you have.