I never thought I'd use one, but a little over a year ago, I started playing with a Peter Gabriel tribute band. I bought a 6 string bass to mimic some of Tony Levin's early Stick work and found the scrunchie thingy (gruvgear) pretty useful. I don't love it, and I move it behind the nut any time I don't need it, but again, it is useful in certain situations for stopping sympathetic string vibrations.