Yes, honestly never really got much out of them, but they are a quick, easily demonstrable view of hand strength. I got more out of fat bar work, and timed heavy holds. The grippers also work best with timed holds, and not reps in my experience. Also watch yourself, because it's easy to over work the grippers, and that carries over to all lifts.
Also really work the thumb, and finger tips with lighter grippers and heavy rubber bands for the thumb extensors.