Most likely thing to be stolen from my car is probably wheels, catalytic converter. Both of these require jacking up the car, shoving some bricks under it, and stripping the parts in a matter of minutes. All I need from an alarm is something that takes care of that scenario.
If someone steals it the car they have - as the article says - likely done it the easiest way: they walked in my unlocked front door and took my car keys when I wasn't looking.