I think the main problem with this is that not even ugly people want to look at an ugly person for longer than they have to, regardless of whether or not it is relatable that the character is ugly. Making them pleasant to look at also gives a bit of wiggle room for failure in case you don't hit the mark.

Secondly, a character being ugly or even "relatable" doesn't automatically make them a good character. Is it possible to have a good ugly character? Maybe. Sure. But as long as we're going down an exhaustingly long marxian checklist of "relatable" things to shoehorn in, you don't really get to have that.