Helpful? Sure. When I played Knights of the Old Republic II (a very glitchy game), the second time I went though it, I used glitches I had read about online. I found them to be very helpful, but in the end, I didn't quite feel as satisfied as when I didn't. Of course, on the second run-through, I was a Sith, and I didn't enjoy that much.
So, in closing, glitches that affect gameplay can be helpful, but not always satisfying.