As a stat, Win Probability Added doesn’t have the cache of WAR. But I like looking at WPA because it does something that WAR doesn’t: it attempts to tie on-field performance directly to a given game’s won-loss result.
Does it do a good job of this? I have no idea — I can barely even understand how it’s calculated. (Here you go, try to figure it out for yourself.) But, nevertheless, I think it’s fun because it captures the way your emotions swing from one play to the next during any particular game. And if you want to take that to the next level, there’s Championship WPA, which takes the extra step of looking at every single play that takes place on a baseball field and attempts to measure not only how impactful each play was on each game, but how impactful each play was on the entire season.