There was a book cover, of a memoir by some precocious British writer, I forget the name now.  On the cover was his pic, and the collar lacked stays.  I thought it was a great look.  The collar was sort of popping up a bit.  I think deliberately not putting stays in a shirt (or at the very most using flimsey plastic ones - so as to not make collar too rigid) can be a cool look.  My experience is mainly with RTW shirts though.  Tennis collars.  Some spread or semi-spread collars, bespoke, but come to think of it, with a four-in-hand, they don't really seem to need stays.  Whether that's because I've starched the hell out of them (I usually use no starch) or because the collars are lined or fused or whatever, I don't know.

I will use plastic collar stays but I cant stand the mettalic ones. Sometimes I forget and my collar curls a little, no biggie.

On a related subject. What I dont like about the top of a collar's edge is when the cotton is too fine and soft and ive been cradling a phone for a while and the collar top get crushed a bit downwards. Now that's sloppy. That is why 100s cotton can sometimes be superior in a business environment.

I recently purchased silicone collar stays.