Not use, sanitation. One person in a 425 gallon hot tub is the same as 80 people in my 34k gallon pool.....
***when we are talking about FC consumption and filtering.
Imagine if I threw a raging party everytime we used the pool. That's what I'd need to do to blow through 7 ppm (?) per use in my pool. From a maintaining perspective, hot tub bather load is insane, compared to a pool.
The hot tub will require alot more attention per bather hour. The same bather makes up to 80x the dent, depending on which one he hops in. That, to me is insane.
Sure, that comparison makes all the sense in the world, but remains abstract to those of us without pools. We gotta do what we gotta do and the comparison doesn't alter the equation.