To put it yet another way, money is a ledger. With fiat currencies like the dollar, that ledger is centralized. And that gives the central authority responsible for maintaining that ledger tremendous power, power that history has proven will inevitably be abused. With Bitcoin, the ledger is decentralized. And that means that no one individual or entity has the power to arbitrarily create new units (thereby causing inflation), freeze (or seize) your account, or block a particular payment from being processed. We've had decentralized money before. After all, no one can simply print new gold into existence. And the "ledger" of gold is distributed because the physical gold itself (the "accounting entries" in the metaphor) is distributed. But with gold, that decentralization comes at a heavy price (literally). The physical nature of gold makes it hugely inefficient from a transactional perspective.
Enter Bitcoin.
It is the first currency in the world that is BOTH decentralized AND digital. It is more reliably scarce than gold, more transactionally efficient than "modern" digital banking, and enables greater financial privacy than cash. It could certainly still fail for one reason or another, but if it doesn't, it has the potential to be very, VERY disruptive.