Batman's contributions to the Justice League include his vast wealth, Wayne Enterprises tech, and strategic mind.
Why does he go out into the field? He could just use a communicator from the Watchtower Satellite or the Batcave to do his job right? Like Batman Beyond?
He's the most vulvernable member of the team and probably the slowest. I could see him getting in the way or being a physical liability in Darkseid/Despero/Doomsday type fights.
I know that I could be wrong, so I'd like to hear your thoughts! But I do not think that he should be leaving the watchtower/batcave as often as he does for Justice League-related missions.