We never seem to see people complaining about what nuns wear, which I find to be a double standard.

Different context. Nuns wear their costume when they are serving. That's why you don't see nuns in full dress at Walmart.

But I see women in full burkas (always with their husband, of course) struggling in everyday situations.

If the religion requires it, it's a terribly oppressive one. These women "chose" not to face consequences, so they wear it. That's why there are international protests by women who call to reject these fabric cages.

No. Majority of women wear it because of sexist opression. They don't have the real choice of not wearing it even if they believe they wear it "because I want to".

Also, using nuns is not a valid argument, because

1. it's a uniform and
2. nuns are nuns because they devote their lives, amongst other things, to not have children. Do those women depicted swore chastity and celibacy?

Neither do I care what people wear. I'm just stating a misleading factor behind the attire.

Also, I never see nuns in public.