I am not exactly sure where you got the "class name" part from, I've typically refereed to those as kernel filesystems or sharp devices. For the record these kernel filesystems are not technically 9p, they present an interface much similar but reads and writes to them are not marshaled and unmarshaled from 9p. It is however possible to export their files over 9p if one desires, I can import a remote machines /net stack and use it to announce or dial out. Plan 9 gives us proto-VPNs just be virtue of its design.

There was perhaps a time where the differences between having everything in binary ioctls and bound to specifically one device was a necessary component in order to reach reasonable performance, but I don't believe that is the case anymore. Anecdotally these days everything on Plan 9 feels snappier. We have some benchmarks that show that 9front outperforms linux with naive pipe io and context switches. What Plan 9 misses in micro optimizations it makes up for by having a incredibly consistent and versatile base.

I want to reiterate the benefits of the network transparency by talking about how drawterm works. Drawterm can be thought of the plan 9 equivalent of windows RDP. How it works is that internally drawterm creates routines to expose a /dev/draw, /dev/mouse and /dev/keyboard through whichever native way there is on the target system (macos, windows, linux, etc). It then attaches to the remote system and overlays these files over a namespace. Programs like our window manager rio can then be run completely transparently, forwarding not compressed images, but individual draw RPC messages. There is no need for any special code on the plan 9 host side in order to accommodate drawterm, again it is something that just falls out of the core design of the system.