I don't think so. I don't even think it's cute when a baby who has to wear them is wearing them.
I hate it when I see a baby or toddler out in public wearing a diaper without any clothes over it.
It's not cute when a baby or toddler wears just a diaper and certainly not when an adult or older person wears just a diaper.
If you have to wear a diaper then fine. But keep it covered in public.