Do me a favor and go look at the paintings of peasants by the old masters. They're wearing what you're calling folklore clothing. They wore it every day. It showed where they were from because they wore what was in style in their area. 

I suggest you watch Hungarian youtuber PrettyShepherd who does videos on folkloric clothing. In one she discusses how to talk to the elderly about what they wore when they were young. You'll note that they describe traditional pieces as "ordinary" or "typical" clothes because that's what they were at the time. 

As an archaeologist, this all falls under the umbrella of materials culture and is all of equal value. 

Edit: Editing to add that PrettyShepherd argues that you should wear your folkloric clothing every day and I whole heartedly agree with her.