I doubt you need them unless you level the truck.
On my sig 2005 Dodge I have them and now that I took out the 2" level (Now have a 1") I rarely need much more than 10-15 psi in them for the trailer. If I had no level I doubt I would need them at all for the TT, but still use them when not towing and loaded heavy.
On the level kits, they do decrease ride quality. I haven't ever driven my truck without a level kit but the front suspension is much softer on the 1" than 2" due to the angle of the control arms. I am not sure how that is going to be effected on the new 2014 2500 front suspension.
The rear suspension also rides better as I can let it squat about 1-1.5" and use less air, all in all much better without a 2" level.