I assume what I'm looking at is the stock (under axle mount) spring snubber. My CJ5 has stock springs mounted over the axle...should these even be on the Jeep now?
I've never seen one before, But it looks to be original equipment. Some sort of overload device. I would think it would be hard on the springs when in use. I would take it off unless you are going to haul heavy loads.
If you had filled out your profile it would have told us what year and drive train you have. That would make it a lot easier to give you an intelligent answer.
It is a win -win thing. You get a good answer and we look intelligent.