Not necessarily, if the user/pass is stored by the browser addon in-memory for the current browsing session only. The user will then be slightly inconvenienced by having to enter a user/pass in the morning, but during the day as long as it does not close the browser, the browser addon can periodically login+logout on behalf of the user to check for new transactions.
Also, how is this different from browsers themselves saving login username/password for the user (by explicit consent from the user). Do banks in the US explicitly forbid this browser feature?
