In various scenarios it is useful to compare multiple data sets on different surface layers. In ArcScene this was achieved by picking an elevation from any surface, either by loading it or picking an open elevation layer, in the layer properties. It was easy to drape an orthophoto in its DEM or to drape temperature grids over a snow surface.
In Pro the workflow is more cumbersome if multiple different layers have to be draped over different surfaces. First the elevation sources have to loaded one by one as surfaces in the scene properties. Only then can they be picked as surfaces in the layer properties.
It would be more straightforward to load a surface straight from the layer dialog of the layer to be draped or, to improve the workflow from ArcScene, as a quick icon in the context menu. Please consider making the elevation surface a property of a layer rather than a surface in the scene.