What can you do with vice grips? Well, I just helped a friend replace the half shaft (not sure if that's the correct term for it. The drive shaft going from the transmission to the wheel on a front wheel drive car) on his old Honda. We used vice grips to pull the old, rusty cotter pins from a couple castle nuts, to turn a nut we didn't have the correct size socket for, and a couple other things I'm forgetting. They can be used as improvised handles for saws, screwdrivers, files etc. They can be used to removed headless nails, bolts with rounded heads and similar stuck fasteners. They can replicate any size socket or wrench. They can be used as a clamp, or as a means of suspending something without a convenient way of tying it out of the way.
Although they are the perect tools for their own particular niche, they can also be adapted to do the job of lots and lots of other tools. Can they do them as quickly, easily, or efficiently? No, but if you don't have the other tools available you can make them do damn near anything.