Yeah, it's basically revenge but also I would argue that it falls into the League of Shadows ideal of resetting the balance by making a part of humanity serve as an example to the rest. Batman suffers for watching his own city fall apart but also to horrify the world by watching it also fall apart into chaos and violence and rattle the cages of normal society.

As for Batman's 24 hour trip, yes it's a plot hole created to add tension, but even if he is broke, he's still smurfing Bruce Wayne, I bet that local warlord who owns the pit owed him a favor.