The difference is that it would be permitted - and I don't see how it would add any more certainty. Modders are still going to be doing that the same way, and it just adds a new officially-endorsed way to put my character in gear that I didn't pick and don't want to wear.
I don't see these as comparable at all. My character in a low-res version of the game is still my character. Spell effects are not personalised.
Because I put time and effort into picking lore-appropriate glamours that suit my individual characters and taste in clothing, and that is how I want them to be seen by other players.
And as I said before, the majority of de-glamoured outfits look dreadful, even before you get into whether I want it for the character.
I don't think people realise how many good immersive outfits they'd be losing alongside the few bad ones.