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.

If you plan on doing high end stuff you will want all your weapon skills maxed. there are events where you have to use different weapon types. I carry my 2.0, Rod of Shaded Wrath and Warspear of Vexation at all times.