Right, but you're not comparing visually similar settings then. So then what's the point? Just to say at worse visuals you can get better framerates? That's pretty common sense, but the point to compare is with similar visuals. And it's a bit of a pain to downgrade too.
Plus the game is incomplete on PC if you downgrade AFAIK, and it will make it super difficult to mod (mods need latest versions), and saves won't be cross-platform compatible either, like in the case of The Witcher 3, if you want to play on Switch 1 and Steam Deck, you can't downgrade the Deck for better performance, as the saves won't work then.