The Club is not an invincible magic bullet.
Yes, if the thief comes equipped with a saw and is prepared to sit in the car hacking away on the steering wheel, it can be defeated. Either way, that takes time, which is something a car thief hates; and lets not overlook the fact that most car thieves are punk kids who aren't exactly 'well equipped'.
What the club is is a target hardener. It's not going to defeat the hard-core professional car thief, but that guy only steals maybe 5% of cars. The other 95% are stolen by punks and butthead kids, who steal cars as targets of opportunity. This is the group the club is for. A clubbed wheel makes it just *that much* more difficult for them to steal your vehicle, which for butthead kids, is all that's really needed to cause them to move on to the next poor schmuck who's car isn't Clubbed. If you have a car of unusual desirability- where you may face prepared and experienced thieves who come equipped and are willing to take the added risk- then yes, additional anti-theft measures above and beyond just the Club need to be taken.
Look at it like this...
Do you have locks on the front door of your house? Bolt locks, knob locks, etc? Of course you do.
Well, all those can be defeated, too. They can be picked, they can be overcome with brute force. Still, they serve a very defined and relevant purpose. This is in the same philosophy as the Club.
My own anti-theft package is pretty simple.
I lock my doors. Functional security Layer 1.
My radio has a detachable faceplate. Functional security Layer 2.
I Club my steering wheel. Psychological and functional security Layer 3.
I have a bluff light installed on the dash that blinks red, so the car appears alarmed. Psychological security layer 4.
If all that fails- if I run into that bound and determined thief who is willing to go balls out and give it a shot in the face of all that, they're not going anywhere without the battery link disconnect key, which I remove every night. That's the last (and most difficult to overcome) security layer...
Cars are very expensive.
For those of us who must live in places where they're regularly stolen, adding target-hardening elements is crucial in making our cars a less desirable target for theft. For a mere $30, adding an additional (and meaningful) security layer to help protect them is a perfectly sensible thing to do.
The only real practical advice I can give on the unit itself is to replace it every so often. Good rule of thumb, when you get a new car, get a new club. The locking mechanism can wear down over time and the extension bars can get sloppy with wear. Also, make sure to put your spare club key on your spare car key ring in case your main set gets lost.