Flap sander - video

[Jon]

Flap sander. By Cazual Haze. 32:59 video:

[TheElderBrother]

For your next trick, tell us how this is more useful than a disc grinder, or a belt grinder. It looks like the brushes are a bear to make by hand, and the machine doesn't do anything any better than existing disc and belt grinders.

I could be missing something, but if i am, it's something arcane...