Partly because NSFW AI image generators like nectar are trained on the tastes of the average coomer that likes those sorts of facial features probably. Also asian models tend to do their makeup and photoshopping in this weirdly childlike way (pointy chin, perfect skin, big eyes). And because coomers fetishize asians, they like to generate their porn like that.

The rest of the body is fine imo (apart from the unrealistic body standards) but the faces always look weirdly young.