The Diamond is simple. Like stone-age simple. That's the beauty of it imo. Lots of things(cars for one) use belts/pulley's to get the job done.
The problem is simple don't come cheap, not if it's built to last forever, the 1/2" automotive fan belts will never wear out, neither will the motor, designed as a fan motor, for years of continuous duty usage.
But, simple isn't the same thing as cheap, and that seems to be what some people want, cheap! Only thing is, cheap comes at a price too, called sub-par performance and longevity!
As long as it looks like a duck, quacks like a duck, who cares if it can fly like a duck!!!