I should start a label category of "things I don't understand." That would include Spandex garments worn by bicyclists. I understand that for performance athletes (Olympics, Tour de France) the minimizing of wind resistance is crucial. But for the recreational cyclist who is out for an afternoon of exercise, why not wear baggy clothes to increase resistance and get the same exercise in a shorter period of time? Why (top photo) wear resistance-minimizing clothes and then add a parachute?
There apparently is a "chafing" aspect, but that wouldn't apply to the Spandex tops worn with the shorts. Maybe it's a perspiration-wicking thing. But I suspect it's a marketing thing... Doesn't matter.
(photo credit here, with additional discussion)