Bitcoin is much more than just a digital currency. It is a protocol, a network, a currency and a transaction language. Most of all, though, it is an application programming interface (API) for money. Nowadays, bathroom scales and fridges have APIs, so why not money?
Traditional money does have APIs, but they are closed. You can program the merchant API of the VISA network if you are a trusted merchant. You can send and receive FIX messages if you are a stockbroker or exchange. Regular people, however, don’t even have APIs into their bank accounts, let alone the broader economy. Bitcoin changes all that by not only offering an API for accounts (wallets) and transactions, but also making that API available to everyone.