Do you mean the all in one things with loose trousers, or the shorts outfits? For either, I agree - nothing worse than fat people with elastic (well, the woman I saw today in a boob tube and no bra, halfway down her bodice, took some beating :-(
I wore them back in the 60's, ha, ha. And then again in the early 70's, when I was long and willowy and I loved them. Now am not so long and more like a blooming oak tree.
They were popular in the 70's and you could wear a maxi skirt over the top if you so wished. I remember having a black satin one with a zip which I wore with long black patent laced up boots -
Well they were playsuits in the 60's. I think catsuits had long trousers (I wore those too) I think in the early 70's they were hotpant suits. Yes Emma Peel wore them and Purdy too!!