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.
Hero's Shadow Health: same as hero Speed: same as hero Attacks: same as hero Counters: same as hero and other stats: same as hero Description: a darker version of you, allowing you to take on the greatest enemy in the game. The gold reward could be dependent upon your level. as all the stats would be loaded form the autosave's hero the programming would be relatively easy. This character could be faced in some dark crypt born from ancient dark magics, created by the shadowlings as either an enemy meant to destroy you or as a trainer meant to test you to the limit of your abilities. The character could also be a mechanical monstrosity created by the mechanics.
[spoiler=The following is considered by many to be cheating (including myself) and is only accessible through a glitch in the game.] This glitch can now be accessed in the full release. At any time go to the mechanics base in the great forest and do the battles there. After you defeat each wave it will place you outside. Quit the game and go to map editor. By going to save/load and pressing the test map button you can play with your characters. You gain the experiance and money from the battle and it loads (if done properly) the text box just after the Mechanics base.[/spoiler]