I don't think Aloy is at all an ugly character, but it is undeniable the real actress looks better. Making realistic faces for character models is hard. We as humans are super tuned to even minute details, to the point anything being slightly off can make a character look very weird.

Look at these face scan images, for instance. There aren't any super obvious differences, but there's still something about it that makes the real actress look a lot better, at least for me.