Workflow from Houdini Engine -> Substance Painter -> Unity/Unreal?

Traditionally we do 3D sculpting/modeling/retopo in DCC, UV unwrap, texturing in Substance, and then we get game-ready assets to use in Unreal.

Now we have Houdini Engine, which allows us to use HDA directly in Unity/Unreal. But how Substance fit in this workflow? As far as I know there is no way to use HDA in Substance, right? So do I still need to export .obj/.fbx first? But if I would export .obj/.fbx anyway, what’s the point of Houdini Engine? Is it only for assets that can be procedurally textured?