One of the uses could be to create a terrain generation tool with support for many types of terrain creation techniques (which could be easily mixed) => . On top of it you could use Houdini dynamic engine to properly simulate rocks other things etc. Create assets and add fracturing for them (really good looking fracturing, not some shitt*y one), then automatically process those fractures and generate proper texture blends etc.
Another plus is that you can have the same tool for UE4/Unity/Maya and get exactly the same output in each. You create terrain tool, load it to each of those apps and work with exactly the same parameters. You update the asset, and it gets updated in all those three at once.
Example of a more procedural pipeline (Substance + Houdini) =>