i am sure, that if i had telephone with directional brain wave reader, i could program it, analyze waves and so on...
it can be used to control computer thus any machine. it can even hack.
it can be used to survey The Internet, to be more alert (like Dragonfly).
i think most challenging aspect is training operator of such phone. we do not want to unconsciously hack our rival. thus operator must control his own thoughts.
Buddhism is key to this.
Subconscious hack is also very bad. See 'Forbidden Planet' film.