Indeed, some arguments to use it but on the other hand the result is unpredictable due to a large variation of parameters in different coffee.
However if you're not satisfied with the used (brand) instant coffee you can still drink it
It will indeed work as low contrast developer and therefore even suitable to use it with the new Rollei ATP-V1.1 Tech Pan film.
One of the lastest Caffenol articles is in the new magazine from Mr. David Vickers:
Enjoy also this new magazine ..... and your coffee