They can get quite busy during peak times and around certain areas. It really depends on what rider promo offer they run that week. Same for Ola.
Didi is not very busy compared to Uber. Whereas I used to average 80+ rides a week in Melbourne Eastern suburbs per week with Uber, I only manage just over 30 on a reasonably good week with Didi. In the same areas. I have found that during promotions I receive even less ride requests. More drivers on the road sharing the load!