(Point of pedantic clarification: I'm really using lowercase-B 'blockchain' to really mean 'distributed ledger', of which the capital-B 'Blockchain' is a form.

(Point of pedantic clarification: I'm really using lowercase-B 'blockchain' to really mean 'distributed ledger', of which the capital-B 'Blockchain' is a form. Distributed ledgers that do not rely on mining or 'coins' have been proposed, but obviously haven't been implemented broadly. So let's limit this to the Bitcoin/Blockchain archetype.) So to answer your question, a couple points: 0. You can use the blockchain without bitcoin as the token of choice. You create your own limited tokens and go from there. This has already happened with various altcoins. 1. You can create private chains. Bitcoin mining and the associated value (currency) therein is one way to create a (public) ledger, but not the only way. 2. You don't 'load your USD' onto the blockchain. That ignores the point of a distributed ledger. Emphasis on that last word, because what we're talking about here is a trusted record of transactions. That's why the blockchain isn't just about currency, and gives participants a way to immutably record all kinds of things.