Yeah it often is described by Klingons as a monastic weapon, meant to teach a lesson or discipline while training with it. I don't think the idea is for like a formation of Klingons to march into battle all wielding Bat'leths.

You train with a Bat'leth and then when a real battle comes you are more prepared to fight with other weapons, or even unarmed. It even makes sense in that the Bat'leth is a very complex object. I can totally see how simply trying to spar with it would force you to think more about all the different ways you can use the thing in your hands to your advantage.