Indeed, there are very few other games in which losing is as fun as it is in AI War. I don't feel like I'm losing, because I get the impression that I'm improving in a meaningful way for next game. Ever since I started really challenging myself in AI War over the past few weeks, I've realized my critical thinking skills, calmness under pressure, and micromanagement ability have all skyrocketed, and it's really helped me to focus in other, easier games I play as well.
It's kind of like when runners train in high altitudes (or for anyone who watches DBZ, Goku training in 100x Earth gravity) - when I go back to the regular tasks they seem simple in comparison.