One big benefit of the 100-point scale is that it has given winemakers a target. It's one way for critics to show vintners where their strike zone lies.
Consumers embraced the scoring system a long time ago. Vintners were more skeptical and cautious. They can rate their own wines intellectually, by flavor, density, balance—any number of ways—but assigning a number, or even using the esoteric descriptors most wine writers use, hasn't fit their comfort zone.
That's changed. Now many vintners I taste with use the 100-point scale. They use it in in-house tastings (often blind). They use it to calibrate their excitement about a wine.
Many vintners have told me that they never thought they'd like the scoring system, but that they now see its merits and enjoy playing the rating game. Some even try to predict a critic's score.
Ratings help sort out wines, and as winemakers assess their wines and their competition, one method is to stage comparative tastings using the top-rated wines in a given category. An easy route is to collect a critic's top-scoring wines and see how their tastes calibrate. Many people will buy wines from the Wine Spectator Top 100 Wines of the Year, taste them and rate them.
Over time, critics' notes and scores come to define the sweet spot. Whether or not a vintner agrees with a rating matters less than knowing how the critic rates certain aspects of a wine, in effect, setting up the strike zone.