But that's exactly what it is. For anything.
And no, an 8 isn't 8, because review scores aren't a science or some standardized measure. Every score from every site is on its own individual scale. There is no standard.
We're not talking numbers. We're talking labels. What are 8/10 graphics or a 7/10 story? The numbers are arbitrary labels, a numerical representation of something that's non-numerical. You can just as easily replace 1, 2, 3, 4, 5 with Bad, Mediocre, Average, Good, Excellent, and nothing would change