Since Mars doesn't have the water-based erosion in areas it was trained on, it loses a lot of the sharper cliffs and adds gullies in places that would be smooth sand on Mars. It would probably be pretty easy to train a new model though that could handle it.
Ages ago I was working on a Mars-based game idea and at the time the terrain res data wasn't great. This kind of concept really would have been a game changer (as it were).
I'm curious how it does for non-Earth data. Mars terrain for example.