It’s not just a currency, like fiat money. The Bitcoin blockchain and other public also can read
https://cryptolinks.com/best-blockchain-books Best Blockchain Books permissionless blockchains that followed are payment/settlement networks, and operating systems for a new way of organising society in a more distributed way, among actors who do not inherently know or trust each other, across boundaries of nation states. (Please read this post on Bitcoin vs Fiat for more detailed information).