Maybe I'm missing some assumptions of yours, but for me the reason to do that is to .. protect the ssh login. Who talks about a machine that is owned? This is

Maybe I'm missing some assumptions of yours, but for me the reason to do that is to .. protect the ssh login. Who talks about a machine that is owned? This is about an additional requirement to log on to a service, be it ssh or email. Whether you're reusing your password, sharing it or just use a really bad one this adds an additional step to impersonate you.