You can commit nearly anonymous transactions over long distances with it. It's value over international currencies is in proportion to the size of the black market transacted via BtC.
There are many people out there who don't try to get rich, they simply mine a handful to buy small amounts of drugs on the internet. The "convenience" of that service raises the utility and value of BtC over e.g. dollars.
Of course, I say nearly b/c a dedicated sleuth could investigate a transaction, but ask yourself as a practical matter, will federales go after an 18-year buying a gram of weed via BtC? of course not. The complexity of the BtC transacation obscures such small transactions well into the realm of "safety."