Typical example of a handicap indicator. Sometimes males of a species will flaunt traits that have only disadvantages to signal to females that they're strong, smart and healthy enough to overcome the handicap.
Several bird species have long, colorful tails. The tails do nothing, are cumbersome and make it easier for predators to see the bird, but females are attracted to large and colorful tails because the male manages to thrive despite it.
That's not nonsense I just made up.
https://en.m.wikipedia.org/wiki/Handicap_principle