In all the universes in which bitcoin succeeds, it first succeeds as a protocol for which traditional currencies circumvent their own limitations, as this value is immediate, palpable, and unaffected by bitcoin's scarce use. Only then, once this niche is established, will bitcoin succeed as a widespread end-user currency on its own right.
This paradigm is present in so many innovations. It's simply tapping more readily accessible value as a way to construct a launching pad for further growth.
Sure - the oft cited strength of bitcoin is the ability to send value instantly (if you trust the party, 10 minutes otherwise) and with near zero fees. As a currency, bitcoin is limited in using this advantage because so few businesses accept them, but as strictly a protocol it can enhance dollars (for example) by being the currency of currencies, so to speak. So instead of using Moneygram to send dollars half a world away, I just exchange for bitcoins, send, and exchange out into dollars (or pesos, euros, etc). Further, since it is has such low fees, microtransactions are possible (web content monetization?), since storage requires no 3rd parties, people (worldwide) can avoid bank runs, and since it is mathematically scarce, they can also avoid (hyper)inflation. All with trivial and possibly automated currency conversions. For bitcoin to become a worldwide currency, it must first become a currency of currencies.
This paradigm is present in so many innovations. It's simply tapping more readily accessible value as a way to construct a launching pad for further growth.