Currently, our fiat transactions, aside from physical cash-to-hand, they are "kind-of" safeguarded by the centralized banking system, in-terms of some level of anonymity. You can't walk into the bank and ask the teller to show you your neighbor's financial transactions of last week.
Yes you can if your are a government agent. All the financial institutions have to collect information of your id/address/telefon to comply with AML/KYC rules so that they can give those to government agent when being asked. Essentially you are not safeguarded by the banking system, but totally controlled by the system, they could freeze your account any time
And with bitcoin it is more difficult to know your transactions if you don't go to an exchange that also comply with AML/KYC rules. Although others can see your transactions, they can not do anything about it. While in traditional banking system, those who can see your transactions have the ability to stop it any time