I think there's really two things, though. I'm sure different people are comfortable at different cadences. But if you're starting to bounce at what you consider a high cadence, I think it means your pedal stroke isn't smooth at any cadence. Back in the day I used to do cadence intervals on rollers. I'd go in 10 rpm intervals all the way up to 150 rpm, sometimes 160. The more I worked at it, the higher I could go without bouncing. Obviously I'd never maintain a cadence that high in real riding, but it made me MUCH smoother at any RPM. I think cadence work is valuable for anyone, for that reason, regardless of whether it changes what RPM is comfortable for you.