One thing I used shape tables for was for a fade-in effect. I would draw my spaceship one pixel at a time, choosing the next pixel at random. (I made a tool to help with this, or else it would have been too tedious!) The shape tables were rendered so slowly that it make the ship "materialize" in a cool effect. After this initial fade-in, I would render the ship more sensibly.
Other than this, I never found much use for shape tables.
Other than this, I never found much use for shape tables.