I don't have time and money for a ton of separate hobbies and exercise. So, racing bikes is the exercise, the hobby, the tinkering........all rolled into one.
It used to be gym, golf, and tinker with a drag car. Was more expensive and time consuming.
I'm a strong advocate of people making exercise a hobby. It saves time and keeps you fit. Cycling, running, basketball, soccer, etc......... something fun and active.
I can't do the "go to gym, pick up things, stare at phone, pick up things again, watch **** TV, go home".