Yeah this is a pretty sure fire way to get the altcoins you get from faucets back into bitcoin... but the issue (or better yet, hassle) is having to sign up for the exchange and having to provide an email and all that sort of stuff.  You can easily use Shapeshift.io to transfer your coins back into bitcoin as easily as it is to convert bitcoin into the altcoin of your choosing.  Just make sure to give the correct address so they can send back the coins if the transaction doesn't fully complete, but that's just being really safe in your transaction... usually it goes through very smoothly.