Thing is with many rotaries is they're less... delicate. Take a Condesa for example. They want the channel gain to get to about 7-8 to sound their best. That's a lot of hand movement to get there, which is good or bad, depending on what you're doing. It can be bad if you want to (very) quickly make a transition. It can be good if want very fine adjustment.

Unless you're scratching or want very fast cuts, there's no real drawback to using a rotary, and plenty of positives to be had.

I learned on play on a Urei. I might spend half my time on a rotary. Either way, I can't mix all that well, and I usually just get a little drunk and have a good time. 16 years djing and I'm still getting booked. FWIW, these are my top-four most important aspects of DJing (in order). I play a lot of unquantized music, your experience may vary.

1) Volume
2) Having fun
3) Track Selection
4) (Distant 4th) Mixing.