The method works because a used top notch bike in good condition might sell for $100 on the street. Destroy the rear wheel it is worth nothing. You also cannot ride it away. I use allen skewers on my wheels too. I tend to think that some dim bulbs might think of a bike chained like this as a puzzle to be solved.

In NYC use a cable and U as SB suggests as there are dudes with sledge hammers that will take a shot at a lone U lock just to see if it will crack. It may not crack but will jam. What do you do then?

If possible removing the seat, skewers and clamps also makes the bike worthless or just hard to sell. I also put QR pedals on my bike. If I left it un chained you would usually get a bike with no seat, seat clamp, and pedals.