Pardon my French, but comparing school grades to review scores is bull****
A 6.0 is a 60%, and that's a D-. Anything below 59% is an F, it's a failure. Which is fine when you're grading school things---you have to get at least 2/3 of the things correct (roughly) in order to pass.
But when it comes to games, there is no objective "passing". You're just looking at a number on a scale. When you have a 1-10 scale, it helps to use all the numbers. 1 is atrocious, 10 is a masterpiece. When you're going on the school scale, even though it's 1-10, you start out with 5 being a failure and then going upwards from there. Then you are effectively only given 6 scores max, because what's the point of going lower than 5? If you're gonna do it like that, why not do a 1-5 scale and use all the numbers?
My point is that you need to forget what you have in your mind, unlearn what you have learned (as Yoda said). We have this 1-10 scale for a reason, treat it like you would any other sort of linear scale and
use all the numbers
IMO, of course.