it's imprecise but pretty close to a players value....
I get you on that, I'm just not sold on it being fair for relievers, or comfortable with the limitations surrounding defensive metrics in general, let alone applying those metrics to games that took place almost 100 years before the stat was invented.
Nowadays, UZR has the benefit of having every ball hit tracked and recorded, as well as the players subsequent involvement in the play. Even with that, the inventor of the stat claims it's not really accurate with sample sizes under three years. I don't know how that part of WAR gets tracked for games that aren't even filmed.