To me, that's really where WAR is most serviceable. I don't watch more than a handful of games a year that the Sox are not one of the teams playing. That means I never watch some teams play. I only watch some teams for 3 games and others for 6. It's hard to know anything about other players except through stats, and WAR gives one number that tries to capture just about all aspects of what gives a player value: hitting, power, defense and base running. It saves me from having to look at ech player's BA, OBP, SLG, UZR/150, DRS, Running indexes and more and then compare 12 stats to dozens of other players to try and figure out if the guy I never see play is average, above average or worse than others.
It's not perfect, but it turns a complicated task into an easier one, for me, even though I don't take WAR as the gospel.