It is really only a thing because smartphone OS vendor make it difficult for people to mount filesystem over the network.
If you could ssh/sftp mount from android or iOS easily, your favorite smartphone audio player would just play those files from a remount mount without any need of a streaming server.
Music is straightforward to self-host. Go for it!
Video can be a bit harder if you have to transcode.
It is really only a thing because smartphone OS vendor make it difficult for people to mount filesystem over the network.
If you could ssh/sftp mount from android or iOS easily, your favorite smartphone audio player would just play those files from a remount mount without any need of a streaming server.