Instead it can use whatever is connected to it.
For example someone attached a vibrating belt that always vibrated on the north side of his body. After a while the person wearing it does not consciously notice it vibrating, instead they basically have a new sense - they just always "know" where north is.
Output works the same way - after playing a game for a while you don't need to think: press this finger or that one - you just want the character to do move, and your fingers do it automatically.
If you use a tool for a long time, it essentially becomes (to the brain) an extension of your body.
So same with this device - it doesn't have to be intuitive - after a while it simply becomes a part of his body. The brain does not see it as "else" it's simply another limb.
Put your hand under one of these toys like the image: http://ubuyonline.com.au/images/toys/pictures%20018_0.jpg
Now put an object or your other hand on the other side of the pins (between the pins and the plastic). Watch your transposed 'fingers' interact with the object. Eventually you will start to feel like your fingers have actually moved to the end of the pins.
I think this is the brain rewiring itself to correlate spacial sensation to what the eyes are observing. No matter what causes this, it's an interesting sensation.
http://news.nationalgeographic.com/news/pf/29102443.html
It's amazing how adaptable the human body/mind is sometimes.
It is incredible how flexible the brain is in adapting.