Well, I think there’s a cultural context to this. I find Americans somewhat preoccupied with collars as an index of the ‘formality’ of a garment in a way Brits aren’t. I remember being mildly puzzled by my visiting US students talking about ‘button-down shirts’ and ‘button-down collars’ as if it was some kind of major gesture towards formality.
Long way round of saying that I think the presence/absence of a collar is more of a marker for Americans than British people.