That information is practically public already, since you have to provide it to everyone you purchase from online with your card. If you regularly buy things online with your credit or debit card it's less a matter of if the credentials will leak than when. Regular checking and savings accounts are at least as bad given the existence of Direct Debit, a system where practically anyone can take money out of any account just by knowing the routing number (public information) and account number (printed on every check).
Cryptocurrency aside, just compare that to something like PayPal, where the authorization happens directly between you and the payment processor: the merchant never gets your credentials and can't take money out of your account without your express permission. The traditional banking system has the worst security procedures; the design is reminiscent of the early days of the Internet where plaintext passwords were commonplace in protocols like rlogin, FTP, SMTP, and unencrypted HTTP, when authentication was used at all. The only thing keeping it from complete collapse is the absolute fortune they spend on statistical anti-fraud analysis, which completely coincidentally requires them to have deep insight into every transaction passing through their network. Not that they would ever think of using that immensely valuable data for their own gain, of course. Perish the thought.
In any case, Bitcoin and most other cryptocurrencies weren't built to replace credit cards, but rather to replace cash. If someone steals your cash or you somehow manage to hand it to the wrong person or simply destroy it you can't just call up the U.S. Treasury and expect them to put things right. Holding cash and transacting in cash has its downsides, and yet those same risky properties can be extremely useful if proper care is taken. Escrow and human-mediated reversible payments can be implemented on top of a system of irreversible transactions. The reverse doesn't work; you can't very well run an escrow service where the payer can reverse their payment into the escrow account without following the escrow procedures after getting the goods.
Compared to physical cash, as a digital good crypto has several advantages and a few disadvantages. In the latter category you have the obvious risk of hackers compromising the wallet; IMHO a separate, secure, hardware wallet is mandatory if you keep any significant amount of self-custodial crypto. On the flip side, however, it's not all that difficult or expensive to make your crypto more secure against would-be thieves than the gold in Fort Knox if you're willing to put in a modicum of effort, and the possibility of geographically-distributed encrypted backups makes it much harder to separate you from your money if you plan ahead a bit.