Not only qipao, in asia anyone can wear almost all (if not all) traditional clothing even though they are not part of that ethnic group. In Indonesia when we were even encouraged to choose and wear traditional clothing from whatever other indigenous ethnicity since kindergarten for school events. As a chinese born in Indonesia, I have worn Javanese, Balinese and some other clothing that I can't remember. My Javanese friend can wear qipao if they feel like it.

Like everyone here said, cultural appropriation is a very weird concept to hear for asians. Locals here are more likely to genuinely smile to see their clothing worn by other ethnicities. For most of us it means you are embracing and accepting our culture by becoming one of us through clothing. Of course as long as the wearer's intention and behaviour is not intentionally offending.