It's mostly an experiment into providing an integrated interface leveraging Haskell features (type-safety, STM, etc.) for the whole system: input, display, sound, network, etc. There is still a lot of work to do...
Then in a probably far future I would like to use it to try different (crazy) things. For instance configuring the whole system with type-checked Haskell code (similar to XMonad configuration but for the whole system); provide a better terminal-like interface/protocol replacing stdin/stdout/stderr/term ioctls; generalize Linux sandboxing to all applications (filter syscalls, use namespaces, disk quota, etc.) and manage per-application permissions; etc.
The closest approach is Android which also uses the Linux kernel but doesn't provide a Unix interface to applications.
Then in a probably far future I would like to use it to try different (crazy) things. For instance configuring the whole system with type-checked Haskell code (similar to XMonad configuration but for the whole system); provide a better terminal-like interface/protocol replacing stdin/stdout/stderr/term ioctls; generalize Linux sandboxing to all applications (filter syscalls, use namespaces, disk quota, etc.) and manage per-application permissions; etc.
The closest approach is Android which also uses the Linux kernel but doesn't provide a Unix interface to applications.