It's a bit like using a steering wheel lock in your car. It's not that they can't be defeated, it's just that there's no point wasting time trying to defeat it when there are plenty of cars without one.
Depends on the lock you're talking about. If you're talking about the lock built-in to pretty much every steering wheel, then fine. If you're talking about The Club, then bad analogy.
Thieves actually target cars that use The Club because they don't have to carry an incriminating pry-bar around to break the built-in steering wheel lock.