They should only be used if you have an excellent ‘leave’ command. It is excellent for muscle building and conditioning – many staffies use them and so do the show dogs.
They are not associted with dog fighting and if a policeman was to see a staffie using one they wouldn’t have a problem. As long as you are a responsible owner and train your dog to leave then there are no problems.
If I had space for one, I would let my guys use it…but unfortunately I don’t.