Yeah that was my thought as well. It would have to be rather situational for you to want it. But it does prevent anything that triggers off battle for your opponent and I know a few decks that would find it a little annoying. Some people seem to be leery of it though. I would like to buff it to this, but if not I would accept it in the previous format as well.

Name: Trial By Combat
Spell Type: Continuous
Effect: No cards or effects can be activated on the field during your opponent's Battle Phase.