My bank currently reprompts me for password whenever I make an important transaction (e.g., transferring out lots of $$$, or adding an account). Should they drop that security feature when they switch to passkeys?
A more realistic scenario is where the user has installed a malicious extension that can exfiltrate the cookies. Requiring reauthentication makes an exfiltrated cookie less valuable. While the extra auth step can be annoying, it also provides an opportunity for additional safety checks (like validating that the IP of a request matches that of the recent auth).
but they want to get rid of it and use passkeys instead.