This may be one way in curtailing bring your own device mentalities but beyond that any security system is always a compromise in one way or another. Also it is only as strong as the weakest link and if your the only user logged onto the box via ssh and others have weaker keys then you start to see the flaws.

But if everybody who logs on uses the same level of security, then it is that secure, otherwise it realy is down to the weakest link and even a home box can be taken out by a house cat who can't even use the vi editor.