I like these little deals pretty good. I think they are more for the hunter than the game but I'm fine with that. I shoot thousands of shots a year. Servings last 2-3k shots on the main one I like to shoot and I reserve 5 or 6 times a year most of the time. Taking some of the noise and vibration out makes it more enjoyable to shoot. I can't stand the vibration that runs into your cheek on a crossbow and the little limb thingies take that out.
I really don't think stuff that quietens them down will make much of a difference to animals that can hear many hundreds or thousands of times better than us, but I like the difference it makes to my ears for target shooting. My favorite crossbow only weighs 5.9 lbs so there's not much mass to take the shock and vibration out. These little things tame it down quite a bit.