There are many more things about banks that will become obsolete.
The check book was already on its way out.

Most banks have a debit card now, but does the debit card tell you exactly how much the transaction will cost you? Does it tell you how much balance is remaining? The bank has nothing on this. In fact, the bank may let you spend more than you balance (because they were having network troubles), and then they will charge you all kinds of fees, following from their mistake.

Not only does the crypto wallet automatically do your check book accounting, it saves you in many other ways. If you write someone a check or show them your credit card, they can forge other payments by you. They have all the information they need. And it is done all the time, and it is the reason CC fees are so high (for you and the retailer)

A crypto transaction can be verified that it was you, without ever informing anyone the information to forge your signature. Just the savings in fraud avoided would make block-chain technology better than the bank.