For fitness I'll say yes, although all of my experience is on a stationary bike. I do it for 15 - 20 min x3 a week and it has helped my endurance for being crunched up on the sportbike with my head up. Any activity that is strengthening your legs will help to some degree.
Is it a surprise that at least a couple of the MotoGP riders ride bicycles as hobbies too?
STILL ALIVE UNTIL I'M DEAD