I am primarily a recreational, fitness, greenway kind of rider, but I try to wear brightly colored shirts, especially bright yellow, when I will be around cars. Visibility matters. That may not be the primary reason for some, but it is a valid one.
You can tell I'm not a wannabe pro because I call them "shirts." :)
Good points.
Road safety. For the rider, and vehicles is a good reason to be seen.
In addition cycling clothing helps wick perspiration, keep muscles warmer, and if you have ever ridden, protect you with the padding in the bib shorts.
It’s not all about looking like a peacock.... ;) ;) ;)
When I go for a predawn run I wear a roadworker’s reflective vest. They’re cheap and weigh nothing.