What do you mean you're not sure how useful ">= 90" is as a criteria? You literally said why it is useful in your comment: > 90 GDT is informally considered t

What do you mean you're not sure how useful ">= 90" is as a criteria? You literally said why it is useful in your comment: > 90 GDT is informally considered to be competitive with results obtained from experimental methods. It's informal because we don't have a true "gold-standard" for determining a protein's folded structure – the best we have is experimental methods of trying to determine the structure which still have a great deal of error (compared to other things we can measure). So all we can do is say "the GDT between two experimental measurements (of the same protein) is often around 90, so if we get there with predictive models that's pretty much just as good". As soon as we have better experimental methods for determining protein tertiary structure, you can be sure we will require predictive models to deliver better results too. Until then, the point is that the delta between any two experimental determinations of folded structure is approximately the same as the delta between an experimental determination and an AlphaFold guess. So the AlphaFold guess may as well be an experimental measurement. Except the AlphaFold guess happens fairly trivially (once you give it the DNA sequence[1]), where as the experimental method is involved and expensive. [1] Or the primary structure, I'm unsure what inputs are given to AlphaFold.