Originally Posted by
patentcad
It is related to rim shape, but the rim does not act as a wing or sail. The air offers less resistance against an aerodynamic shape, so it takes less watts for you to propel the bicycle forward.
But mostly, yes, it just looks cool.
Except for the giant sail that is your body slowing you down.
Let's face it. You can make a bike as thin as a sheet of paper but when you sit on it you are the biggest wind drag imaginable.