I'm personally not fond of it. With how significantly general variance can influence the metascore of a game because of small sample sizes (not to mention secondary factors that have little to do with quality, e.g. brand fondness likley inflates the scores of stuff like Uncharted, Zelda, GTA, etc, to some degree), there's very little statically significant difference between an 89 or 90. Even professional polling companies, that are often working with sample sizes of 1000+ people and put considerable effort into weighting those samples correctly, usually have self declared margins of error of 2 - 5 points. Giving a special label to stuff that happens to start with a new digit ends up coming across as a bit silly.
That all said, I doubt much will actually come of it. I don't see people valuing that label anymore than they already arbitrarily value seeing a 9 at the start of a game's score.
