I'm surprised to see that so many people are concerned about ethics of controlling a cockroach. I would like to hear what your opinions are on animal farming and killing in the food industry. Or even killing a cockroach vs controlling it.
And why not an iPhone app? Hackers don't need a reason do something new. A simple reason I can think of is to demonstrate that this is possible and also get people interested in the field so that more research is done. I would very much like to see computers directly connected to human brain and I/O being done on it in the future.