"Bitcoin will do to bank what Email did to post office" - I doubt that bitcoin will get this role. Most likely it will be something like CBDC. Undoubtedly, traditional banks will very soon cease to exist in the form in which they exist now, but they are unlikely to disappear completely. Even the post office still continues to exist, although its influence is completely different from what it used to be. The same will happen with banks.

The reason for the restrictions imposed by various countries on bitcoin is that control over the financial flows of citizens is lost. Now whoever controls this controls the world. Bitcoin creates a lot of problems for governments: you can’t find out the owner and recipient of a wallet, you can’t freeze or ban a transaction, you can’t understand who and to whom, and also why you sent the transaction (of course, with reservations). From their system's point of view, everything that happens on the BTC-network is below their radar. And the fact that money flows from traditional banks to bitcoin thanks to investment is secondary.