Im training in the R22 and I always wear mine. I have a SPH-5, which I was lucky enough to pick up second hand from another pilot I knew.
To use your new survival gear youll have to be conscious RD
Go through accident reports and stories and they are just littered with stories of guys who would have survived had they had a helmet. Dont forget death isnt the worth thing. A good whack to the head and youll spent the rest of your life being spoon fed.
As has already been mentioned its much quieter inside the helmet. I personally find the helmet much more comfortable than a headset as well.
One more thing, I find that in the 22 I fly without doors 99% of the time, so a little extra protection never goes astray.
I seriously doubt that I would fly without it now.
Fly Safe.