Nanite is probably not super performant either. But I’m not worried about performance yet. I’m solo, so by the time I’m ready to release anything (assuming I ever get there at all), hardware will have caught up 
Just that it is supported so I can actually use it for development, is good enough for me.
Also, outside of VR, I get pretty reasonable GPU usage with or without Lumen (quite recent but not latest hardware), so I’m guessing there are still possible improvements even on software only.