It would be nice to be able to intersect two transient surface bodies in the API without having to create a 3D sketch first and using that.
Creating the 3D sketch and having it populated with the intersection curves slows the process down considerably, even when doing it in an invisible document.
Also, it seems CurveCurveIntersection for transient geometry is only available for 3D curves, but not for 2D ones. It seems odd to me that the simpler case of intersecting 2D curves has to be upped to the considerably more complex and error prone 3D case.