Oh, I had a pair of convertible shoes like this in the 90s!!!!! What moment of nostalgia. I absolutely loved them. They had a wooden sole, were made of brown buttery leather, and had a fold that made the conversion easy. They were comfortable either way and were not ruined or damaged by the fold. The 90s was the time of mules and I loved being able to switch back and forth.
Tho I also remember doing this to sneakers because yes, it was the fashion at the time. You'd do it long enough and it wouldn't be uncomfortable.
But yes, doing this now to shoes not designed for this purpose--no, no.