If you choose bolder colors for cheongsam (e.g. dark red), you can still wear it for D&D, formal functions. etc. That was what I was thinking. My partner secretly wish I wear one everyday! duh...
You are right on the changing of attire. Cos in the old days, the bride don't go back to her parents's house till at least 3 days later. Reason is the travelling distance (last time they have to walk, ride horse, cross river etc.). Therefore the change of clothes, we call it the tea dress now. The groom need not necessary wear the same suit. Another reason is, the woman belongs to the man's family now so she cannot suka suka go back Niang Jia. So go back, is a much casual affair.
So when the bride leave her parents's house after the groom fetches her, she is (supposedly) wearing the gown (in the old days, will be the red kua), so bride and groom serve tea in the wedding gown (or kua) and suit to the groom's parents/relatives. Then they change clothes either at groom's place or their new place, then they go to bride's parents's house.
Having said that, things have evolve. Only cantonese brides wear the kua.