The world is still deciding what Bitcoin does as well as how is should be classified, after it's inception twelve years ago . Practically, Bitcoin isn't isolated from the traditional banking system because its price is supported by USD bank liquidity making its trade as a speculative asset rather than a currency.
You don't need to rely on others, banks to use your bitcoins in a way you prefer.
Do you know about a first transaction between two people, peer to peer, on-chain, Satoshi Nakamoto and Hal Finney?
Did they need any bank to accept bitcoin to make that transaction?
Did they need to have any USD liquidity pool to make it?
Payment No. 1: A Closer Look at the Very First Bitcoin Transfer.
Did lazlo need any thing else to make his trade for 2 pizzas?
Pizza for bitcoins?