Plex has been around quite a while longer than JF. Before JF, the only way to really have a "self-hosted Netflix" was with Plex, so there are a lot of us who built our long-standing media setups around that.
That said, I have a JF instance running and matched almost 1:1 with Plex specifically for this situation, so I'm going to start pivoting everyone to that as I wind Plex down.