I do agree with this. If there was going to be any sort of "style restriction" to prevent immersion breaking then it should have been implemented globally from the start with stricter rules about gear design styles. Keep everyone on the same page and in control of their own character, just be more selective about the choices that players are presented with. But that's a horse that has long since bolted.
That said, an "FF vibe" can be anything from high fantasy to modern to sci-fi to whatever part of the fantasy kitchen sink they feel like throwing us into today.
While I appreciate the more high fantasy side of things myself, a lot of people seem to be looking to the more modern outfits. I don't know what research is guiding their decisions on glamour gear, but it's going over well whether I like it or not.
Ultimately, if SE had any intention of protecting us from immersion-breaking glamour then they'd stop putting in things like the Namazu and bunny outfits.
To be fair, glamour isn't just about dressing up for others. It's also about creating it for myself. But - like picking clothes in real life - any outfit I've put together for my character will be based on the two important questions (a) do I like how this looks? and (b) am I happy to wear this in public?
Sometimes I do make glamours that don't fit that rule. There are some that I've put together and taken arty screenshots of, but wouldn't wear in a town or dungeon. (To be clear, things like a White Rabbit costume that looked great in the specific pictures I took but stood out cartoonishly anywhere else, or a set of themed glamours I'm working on that will need some of my characters in elaborate robes they wouldn't normally wear.)
Much like in real life, as a cosplayer, I'll wear a costume at a convention but feel dreadfully silly if I have to wear it while getting there on the train, and certainly wouldn't wear the outfit "as myself". And still I pick costume choices based on my own taste in clothing - though at least with the choice to add tights under skirts if I want.
So yeah. On the one hand yes, glamours are "for me", but that doesn't mean I don't care about how my character is presented to others. The two things are intrinsically linked.
Edit to add: I have just as much fun dressing up characters in single-player games, on the rare occasion that they have complex customisation options like this one.