So long as the mutton is nicely seasoned I still will give it a go, though I wouldn't do this, as I believe it's a jumpsuit. My bladder suggests jumpsuits with belts are no longer a good idea.
I do believe in the general concept, mutton dressed as lamb, but no longer really care. To be honest I often heard Dad say to Mom something along the lines of "You're not letting her out of the house in THAT, are you?!?!?" Yes, she did, and I still will wear odd stuff. Too self conscious to dress too "normal". Have always thought people were staring at me, so, gave them a reason to look. Did wonders for my confidence level.
If you like it, make it and wear it. I occasionally make something really out there that I assume might be best suited to alone time in the house or back garden. Today I'm wearing slightly dropped crotch floral bloomer/harem type pants that are a bit too show through in sunlight. I'm comfy and they make me smile.