Not an expert there but Ive always understood it to be cosmetic.

I think it's a combo situation. My canines don't align top and bottom, so they are putting pressure on weaker teeth causing premature wear. Doesn't hurt to get a sale either.

Theres an orthodontist that feels its mostly bullshit. Look up Mike Mew, Brett Weinstein. Bretts podcast is fucking amazing. 🍻🧡👊🏻🥩