The problem is that right now most secure sites have only one level of security. Once you've logged in to your bank account to see the balance, you can also transfer money to Nigeria. So if there's any problem with security on your home PC, all sorts of exciting stuff could leak out. That would become more likely once it became common for peoples bookmark file to contain their bank account information. So you'd probably want a strong password as well as good security... and people are very bad at strong passwords (I have two, and change them as rarely as possible, using them to secure other passwords as needed. Even my geek friends comment when I use them, as 20 letters just seems excessive for a password to most people).