I actually do understand what WAR is. I wouldn't have such a problem with WAR if was called something like Combined Offensive Defensive metric. However, if you go to fangraphs the WAR metric is described as follows: (source: http://www.fangraphs.com/library/misc/war/ )
You should always use more than one metric at a time when evaluating players, but WAR is all-inclusive and provides a useful reference point for comparing players. WAR offers an estimate to answer the question, “If this player got injured and their team had to replace them with a freely available minor leaguer or a AAAA player from their bench, how much value would the team be losing?” This value is expressed in a wins format, so we could say that Player X is worth +6.3 wins to their team while Player Y is only worth +3.5 wins, which means it is highly likely that Player X has been more valuable than Player Y.
A team made up of all Replacement level player (R in the WAR stat) is assumed to win 48 games per year (thereabouts, I don't have time now to look it up). So to get to a 0.500 team all players combined need WAR's to add up to an additional 33 games (to get to 81 games) over 162 games (there is some uncertainty, say +/- 5 games).
Based on what I have stated above (from fangraphs) if Devon Travis, who is a plus WAR player, is replaced with Replacement level players (WAR of 0) and other players on the team remain the same then the team should win fewer games. However, in reality this wasn't the case; we know there is some uncertainty so even winning the same number or close (percentage wise) would be acceptable but the difference was well over 10 in the wrong direction.
Please, could people stop claiming that I don't understand WAR. I understand it since it is a simple concept. However, WAR is not reliable in determining what it is intended to determine (Wins Above Replacement).
I believe Devon Travis is a good player, but assigning a 2.4 WAR to him over his short career is meaningless as indicated by his real WAR when he was actually injured and replaced by a Replacement level player (determined directly) with almost all other players remaining the same (the team WAR didn't change significantly until players like Tulowitzki were acquired).
In short, Devon Travis is a good player, but the WAR metric is just an interesting stat which cannot reliably calculate Wins Above Replacement as it is intended to do.