Right now it's fundamental usage is for illegal transactions for obvious reasons (kind of a throwback to Flooz if anyone remembers that, which ended up primarily being a money laundering tool for organized crime.) The only other reason I can possibly see someone getting into it is to cash in on the bubble and make a profit.
Now why anyone would prefer using it or setting up a system to accept transactions in it for legal purposes is beyond me since the only reason I can think of is "OMG MONEY NOT CONTROLLED BY THE EVIL GUBMINT!11!! END THE FED!!!11!!!" Which actually is basically the reason it exists.
So basically it has no purpose but for illegal transactions, to assauge libertarian paranoia, and so that others can make a profit off the idiots in the former group.
BRTD,
Pardon my ignorance but what was Floorz?