Some files are different. So? Do you have the same qualms with stdin/stdout not being seekable because they are often connected to a terminal?
The "everything is a file" abstraction is mostly helpful and rarely gets in the way in practice; I don't know how plan9 exposes sound, but it is probably a directory, with multiple files - one you write to to set sampling rate; another gets data, and the third is stop/go/cancel.
The most useful feature, though, is network transparency that really works. You don't need Vnc/rdp; just mount the remote display in your file system. You don't need special ip forwarding - just mount the remote network in your local file system. You don't need a network aware server for anything - it all is.
The "everything is a file" abstraction is mostly helpful and rarely gets in the way in practice; I don't know how plan9 exposes sound, but it is probably a directory, with multiple files - one you write to to set sampling rate; another gets data, and the third is stop/go/cancel.
The most useful feature, though, is network transparency that really works. You don't need Vnc/rdp; just mount the remote display in your file system. You don't need special ip forwarding - just mount the remote network in your local file system. You don't need a network aware server for anything - it all is.
That's the reason to get excited.