Yep that's the way to remove 'dings'You could make a hole the same size as the tube from a block of hardwood, cut it in half, place the two halves around the tube and screw them together as you wind the block around the dent. That may minimize the dent. May.
I'd ride it if it was cheap enough and i just wanted a hack bike to leave leaning up against lamp posts whilst I was in the shop/pub. I wouldn't pay proper money for it, and I wouldn't attempt to remove the dent or tidy it up. The block of wood trick will not work on any frame tube which was not designed to be perfectly round. You won't be able to recover the dent out of a modern hydroformed alloy bike with weird shaped frame tubes. They were not drawn as cylinders so cannot be "repaired" by the method suggested.