There are many cases where we need the topo mesh to finally be completely solid and still give us plan-area calculation values, this would be a general solve to most topography problems we're having. We could add and subtract volumes from one another and create tunnels, sub-terrain volumes, easier and more realistic sidewalks and roads, rocky mountainous areas that have more than one point in a specific X-Y coordinate with a different Z value, create caves and more. Specially with the help of Dynamo, the possibilities would be endless and achieve high-end industry professionalism.