The USD loads hidden geometry into the scene, rendering animation works from scene to scene (there is animation in the viewport, the first frame is in the render window), breaks the geometry (doesn't always break it during rendering, but often), renders non-existent objects (it looks like intermediate frames ), it is impossible to impose subdivide for smoothing, does not read shading, it slows down very much. Almost all of this is also true for procedural ASS and Alembics
