If your objective is to sell a stolen iPhone then you still have to know the owners Apple ID and password due to activation lock. Being able to bypass Touch ID isn't going to help you.
Correct me if I'm wrong, but I'm pretty sure Apple's new iOS7 activation lock has not been defeated yet.
Keep in mind that if these criminals can't figure it out by googling it, they will give up and move on. The typical phone thief isn't a security expert with the knowledge to invent a previously unknown exploit.