It would help alot instead of trying to make a map on the uneven ground.
Have you ever wanted to put something down on the map and there is an unmovable rock in the way? What about about a hill thats too high? Just think what you could do if you want a hill in one part of the map and a valley on the side. Just grab the ground and lift or drop it. It would help alot instead of trying to work with eneven ground or building above the water.
Want grass? Paint it… Want stone? Paint it… Would make things alot easier than using Tin Cups.