The great thing is you don't have replace your btc to benefit from the transactional privacy that Monero offers if you don't want to

In short, Monero encrypts amounts and addresses so that they are not visible on chain. Spenders are "mixed"/obfuscated.

Amount privacy: RingCT (Confidential Transactions)

Receiver privacy: Stealth Addresses

Sender privacy: Ring Signatures

A nice property of pedersen commitments used for amounts is that they are perfectly blinding meaning even a quantum computer can't break amount privacy.

You can dig into the details on these sites: