In my mind Dragonborns like to give jewelry etc to their partners so their partners are shiny + covered in items THEY gave them like a territorial thing, so Raff really likes gifting Birdie jewelry/seeing her wear it but she doesn't like wearing jewelry because she is like 'i'll ruin it!' so usually she doesn't wear any unless they are going to Draimid aka Raff's home town, then she will wear more dragoborn style clothes and wear the pieces Raff has picked out for her to wear because it is a pride thing, plus it looks good, and it's sorta a 'oh I can tell by your jewelry you're taken/dating/married/etc' so they have matching pieces that signify that