So then why even bother?
I know some people who mine bitcoins do so for the sheer geekiness of it all, the fun of playing with uber PC hardware and making it sweat.  I know some other do so for the idea of perhaps getting back some of their investment in hardware.  But surely there aren't very many other reasons, right?

I guess if someone were to just happen to have a lot of hardware already installed and at their disposal it would seem smart to put it to good use.  But it seems to me in the end it's just a rich man's game.  If I had disposable income I would probably play around with it like this I suppose - it would be fun!