/dev/screen was an example, in practice as said in the sibling comments you'd use drawterm which fulfills roughly the same usecase as what ssh or RDP do, so yes, the use is there. And you may not need a full HD screen at 30 fps to work
But it doesn't stop there. Wanna play local music remotely ? /dev/audio is there for that. Want to use a machine as a jump server ? Just mount their /net folder into yours and any network operation will go through them.
The ideas can be used today. I have a folder of Music with only lossless songs for personal reasons, but it's obviously not perfect for playing from my phone because of how large they are. So I had a server that transcoded them to Vorbis on-the-fly and served them with FUSE, and a sshfs on top of that to serve the transcoded fly to my phone. This composition of a common interface might use no line of code from Plan 9 but it definitely reuses its philosophy.
But it doesn't stop there. Wanna play local music remotely ? /dev/audio is there for that. Want to use a machine as a jump server ? Just mount their /net folder into yours and any network operation will go through them.
The ideas can be used today. I have a folder of Music with only lossless songs for personal reasons, but it's obviously not perfect for playing from my phone because of how large they are. So I had a server that transcoded them to Vorbis on-the-fly and served them with FUSE, and a sshfs on top of that to serve the transcoded fly to my phone. This composition of a common interface might use no line of code from Plan 9 but it definitely reuses its philosophy.