I think it's teaching them that they are not enough.
We should be teaching them to be their best self and to love themselves, instead of teaching them that they need a weave or acrylic nails to look pretty or to impress someone.
Teach them to manicure their own nails so they can be healthy and strong.(If you do take them to a nail salon, get them a manicure instead of the tips.) Teach them how to take care of their own hair so it too can be healthy and strong (and long if that's what they want). Don't teach them that they are not enough.
That's my opinion.