They do have a practical use of course, as they prevent sweat running into your eyes and do not trap heat as a cycling cap would on your head. Most pro cycling teams had a team version and in the days before hard shell helmets, they found favour with the likes of Laurent Fignon, Bernard Hinault, Robert Millar, Laurent Jalabert and Alvaro Pino who were often seen in action back in the '80's sporting the humble towelling lined headband.
We often get asked for them and on a recent trip to Italy, discovered these models nestling in a quiet corner of a major cycle clothing manufacturer. Hence, they are 100% authentic and proper retro. They're also useful for indoor training and to a certain extent, prevents pools of sweat gathering on the garage/shed or even lounge floor! They can also be used as a handy accessory when attending a fancy dress function!
Currently, many track and field athletes sport the band and basketball giant LeBron James, along with what seems like just about every other star in the NBA, are seldom seen without it.