I see them as a leotard which is what I wore when I danced as a teenager, and to my early days of jazzergetics.
We used to wear footless tights or thick nylon tights underneath mostly. I like them for a performer.
I have two bodysuits that I love wearing as a layering item instead of wearing a camisole/tank top. One is black, one watermelon pink. I wear them under sheer or semi sheer tops and it avoids the ride up of the cami which I always get, it also creates a clean line at the waist line which I like, and essentially one less layer at the hips (the bodysuit rather than a cami over knickers).......Mine have the snaps and I find them comfortable and convenient. I would not wear one alone, but I am planning another one for layering purposes.
I had at least three about 1990-1992. Loved them with a power suit or with my 501 jeans.