I assume you are talking about 2H Blunt here. Never been a fan of that skill, as to me it seems the most painful to skillup. I would say yes it is worth it to go ahead and train it if you have the time/patience. You never know what weapons you will come across. I think the 2.0 is probably one of the best, if not the best, weapons for a zerker and it is 2H Slash. But it takes a while to get to the point where you can get it, you might come across a really nice 2H blunt somewhere along the way that you wish you had the skill to use it.