Graphics like monument valley, 2D or 3D best?

So, I have made a small demo of an isometric endless runner and aiming a bit for monument valley graphic wise. It is aimed for mobile only. Is my best bet to go for 3D, perhaps with baked models? Or should I use 2D art? I mean I have demo working but want to add details. Perhaps performance is ok on mobile now to have alot of simple small cubes.

I don't want to show demo yet as I think I have a bit of unique mechanic I want to keep for a bit