WAR in particular gives no real credit for being a versatile defender, unless one is a really good defender. Tovar played a lot of third base, outfield and some in the middle infield, and while he wasn't great, he wasn't an embarrassment. I think managers really appreciate that more than the stats can show. Tovar also never walked much and didn't have great power, so his OBP and slugging weren't very impressive.
Like Tovar, Arraez is valuable for his offense and adds value in a manager's mind by being able to take the field and not embarrass himself at multiple positions.