I thought it wouldn't be, as when you normally win one of those battles it asks you to load a game, but unfortunately doesn't allow you to gain the gold you received by the battle, thereby diminishing the value of creating a map. It's like going to your own deeper downs map, in which you can add more challenging aspects.
For instance, taking on a horde of assassins whilst attempting to take down their leader, the terrible black spriggan. Or, saving a trapped Set from incredible peril as your team is cut off from you and him by an immense ravine teaming with the souls of the dead.
Besides it's as much as cheating as redoing the deeper downs or killing guards for helping beggars, but simply quicker and possibly less redundant.
edit: also this can be seen as a reward for completing absolutely everything the demo allows.