Let me start off by saying that vintage year differences indeed have minimal impact in those wine-producing areas in which weather conditions (macro and micro) remain remarkably stable from year to year. The area that comes to mind most quickly is Chile where, with minimal change in rainfall, wind direction, predictable average weekly and monthly temperatures, well-known patterns of night-day temperature changes, and firmly stable soil conditions, one can almost ignore vintage year in favor of producer reliability. That is not to say that there is no variation. It is to say however that such variation is minimal.
Going in the opposite direction, vintage variation is probably most often noted in what many consider the "greatest" wine producing areas of the world – that is to say nearly all regions of France, Italy, Spain, Germany and Portugal as well as in California, Oregon and Washington States.
As to importance in familiarity with vintages – very - but on the condition that one realizes that vintage evaluations are little more than estimates and averages. True, in cases of catastrophic vintage years in an area or areas, all serious wine lovers should be aware because it is probable that few if any really good wines came from that area or areas during that year. If one does not have a great repertoire of knowledge of wineries in an area, the wines of a catastrophic vintage year are to be avoided. In the case of "great" years, also useful but again, merely as a guide. In the case of good but not great years, more important to know how this or that winery fared because even in mediocre years there will be wines that rise above" the average.
Key principles: Again, even though vintage charts are estimates and averages they can provide an initial guideline; that vintage year data must be factored in with the quality and track record of the winery being considered; and that detailed tasting notes are far more valuable than mere vintage predictions.