A good example of how the numbers game is perceived by the public is to check out the comments thread for pretty much any popular review on Eurogamer. If a game gets 9/10, for example, you will see a procession of comments such as -
"So, better than MGS4 then?" [Eurogamer gave MGS4 8/10, it's a recurring theme)
"This game is never a 9, no more than an 8 at best."
"This review reads like a 7, I was surprised to see the score."
"Yet Halo 3 got 10/10, and this is clearly a much better game."
"This reviewer clearly sucks / takes bribes / has been affected by the advertising."
The thread will later be joined by the 'reviews are subjective / 5 is average' crowd.
Ultimately I think there is some aspect of human nature that likes to see even fairly nebulous concepts quantified, hence all the pointless stats that you see in sports coverage. And don't forget, there are plenty of TL

R people out there, who only want the score - look at the rise of metacritic.
From the point of view of the reviewers / publications / websites it makes sense to include a number and keep everybody happy; these people are mostly concerned about 'bums on seats', not the finer points of the nature of criticism and reviews.