There are two benefits to creating high demand for bitcoins. The first and obvious benefit is that you'll end up with a wealth of bitcoins. The second and more subtle benefit is that as demand outstrips supply, people will exchange local currency for bitcoins which will allow you to more easily exchange your bitcoins for local currency.
however, exchanging other currencies for bitcoins won't create more bitcoins ... so as more people use it, there will be a hoarding of coins [at least according to what we learned in economics, but this may be inaccurate].
to be an "open currency" where the supply increases as user-base/uasage increases is important. at the same time, it should not be controllable by a central source (ex. a "closed currency"), and not be 'faked' into making money, ... so the quesiton is HOW is this done with a peer2peer setup?