If memory serves me correctly (and it doesn't always ;-) the riggers or instructors belt was first made for military instructors in rapelling and parachuting who worked in the practice towers. It allowed them to have a "safety belt" when working around the top of the tower. I had an instructor fall in that type of circumstance before the belt was in common use. It was NOT designed as a rapelling tool. Although it is sometimes used as one, I would consider it an improvised tool, like the dulfersitz or the bowline on a coil. The Swiss Seat, in its many incantations, is a horse of another color. It is a good primary tool, possibly not a comfortable as a well fitted harness, but better than a poorly fitted one and just as safe if you know what you are doing (and you shouldn't be rapelling if you don't). It is often lighter, more compact, more adjustable, and can be used for more than just a harness. I carry a length of web in my SAR pack and often in my work pack for simple situations that may arise. I carry one in my day pack in alpine terrain for simple desent on steep or slippery locations.

Respectfully,

Jerry