I don't understand this. Why? Why couldn't you go for a 30 minutes bike ride every morning as if you were going to work? and go back home? What's the difference?
I think purpose. It's easy to take it as a perk that you can ride your bike for 30 min and get "free" exercise while you go to work. It's a bit different mindset to ride your bike just for the sake of exercising and not having a bigger goal behind it.
It's easy to make the switch though, I did it :)