Can you explain how? I don't have a lot of experience with bike theft, so it makes enough sense to me that the frame being locked would be enough to prevent the bike from going anywhere
I don't bike and can't tell from the pic, but a lot of times the front wheel has a quick release so you can take it off. Then you run the chain through both wheels and the frame.
The front and back wheel can be taken off with a hexkey by literally anyone, great for maintainance, but if you piss someone off they can take your wheel and make off if you leave your bike unattended for long periods of time.