Not the GP but some guesses: If they disappear or change something, it will effectively shut down a lot of sites that does not have access to someone knowing h

Not the GP but some guesses: If they disappear or change something, it will effectively shut down a lot of sites that does not have access to someone knowing how to update to a new cert after three months. Sure, the page will work but most browsers will block the users to get to it or require them to click things with scary messages on them. Holding the key also means they start your engine for you.