The right pitcher getting the win being correct “most of the time” isn’t real useful considering most pitchers get less than 10 wins per year.
A century ago, when the starting pitcher threw all 9 innings, pitching wins were more useful. But the advent and growing use of bullpens has made them a useless evaluation tool. Especially since they did nothing to tell you how good relief pitchers were, which is why ERA was devised in the first place.
fWAR and bWAR are good ones today, whether or not you know how to calculate them. And someday, they’ll be replaced, just like VORP and WARP and Win Shares all were.