The question I wanted to ask, but didn’t.
To my mind it is like bib tights under mtb shorts, wearing (and therefore dirtying and sweating) 2 items where one correctly chosen item would be superior.
Leaving an odd aethetic that is apparently pleasing to its fans, but looks bizarre to other “types” of cyclists and the general population.
There is a lot of tradition in road cycling (and some of it warranted) and the peaked cycle cap was excellent for the reasons given above in the many decades before the era of a) helmets and b) “sporty” sunglasses.
I’m former roadie, I never saw the point.