I’m torn here. It’s a good way for me to talk about my peers (early thirties) in the third person, but it doesn’t quite fit for second person for me. (Edit: ”guy” is also not great for second person, now that I think about it, so maybe it’s more equivalent than I realized. Though for plural third person, it still isn’t 1:1, imo. “Two guys in my class” has a different connotation from “two ladies in my class,” but I can’t put my finger on why.)

“Ladies” feels formal/salesy (if someone addresses a group of women I’m in as “ladies,” it feels like they’re either a server for our group dinner or trying to quickly build rapport) to me, whereas “lady” can often feel straight up rude ( “hey, lady!” sounds like Bart Simpson said it vs. “hey, ladies!” which could mean so many different things depending on the context, but seems less annoyed at least).

While generally true, there are some people from older generations that associate ladies with prostitution as in 'ladies of the night' and find it offensive.

Yes, I have known quite a few and they are in their 60s to 80s right now.