People have wanted this for years and yeah I agree, it'd be awesome.
Imagine ... having a glam plate with a ribbon, and there's a ponytail hairstyle tied to it. So you can wear the ponytail when you wear the ribbon. Crazy, right. Or maybe you wear your ponytail 90% of the time, but you have 1 glam with a hat and you don't like how the ponytail vanishes thanks to the hat. Well now you can attach a "long" hairstyle to the hat glam plate and always be styling.

God I wish this were a thing for everyone, and not just for people who use certain tools developed by like 1 guy in his room for free. It feels so bad how there's gonna be like 2 hours worth of new content between now and next summer, but all this QoL stuff is still terrible after nearly a decade of people begging for better. Maybe in 2024, Square will let more XIV money be used for XIV and not some standalone title that flops, and hire a beefy devteam to communicate with modders and tackle unaddressed quality of life issues hahahahaha *huffs copium* ahhhhhhhhhhh