>>808935The "pillow" for your head is for flotation when you are being pulled in by rope to the raft. It acts as a leading edge to keep your head out of the water.
If it works for you, fine, and the high flotation may come in handy. Personally, I'd suggest a Class III pfd rated for whitewater that sits lower on the torso and has much freer shoulder straps.
Something like pic related
