It all depends on if you need them or not. We've used pneumatics every year I've been on the team, although we
are sponsored by Festo. Pneumatics do come in handy and are often worth the weight in my opinion. Though it does depend on the design.
Also the overhead for using pneumatics is more like 10 lbs. not 15.
You can save a lot of weight by not using all the brass in the kit - there are better ways to set up the system.