I've been bulk loading for a long time and haven't had a problem with scratches. Just lucky, I guess.
Like some others, I occasionally want a short length of film to test a camera or to load certain cameras that can only take a small number of exposures.
For example, I preload Agfa Rapid cassettes -- 12 shots per roll. I suppose I could get a roll of 36 or 24 and cut it in half, but a bulk loader is much simpler.
The Ducati takes 15 half-frame shots, which works out to 8 regular shots or 9 or 10. The Robot cameras also need a special load.
So, lots of good reasons to bulk load your own. Very simple to do. Once you've rolled two or three, it's a piece of cake.