Stelarc: Genius or Lunatic?

Stelarc is an artist who specializes in using the body as a work of art that is undergoing constant improvement and upgrade. Most notably, he has undergone a surgery to graft an "ear" (basically a headphone and microphone rig) underneath the skin on his arm to create a third ear.

Is this actually useful? It really depends on who you are. If you are the conservative type, you may view this as just plain weird. However, from an interactive standpoint, it's quite an interesting concept. If a functional ear can be created on any part of the body, no matter how rudimentary it may be now, the possibilities are endless.
As Existenz portrays, virtual reality is progressing at a rapid rate. Imagine if the devices could be directly implanted into the body. Many doors are opened. How, then, would real and imaginary be defined? Would it be possible to even tell the difference?

It can be easy to take off a helmet (or unplug a bio-port) but it'd be pretty difficult to dig out a machine from inside of your body. The nightmare would be even more real.

To this degree, however, I fail to see a point to Stelarc's "art." It seems as though the ear serves no functional purpose other than to show that the microphone implanted in his body can pick up sound through his skin. And why add an ear to an arm? How does that add to life? Perhaps if used in a more practical manner, this kind of technology could show signs of usefulness, say, in the medical field.