I guess I don't understand what is the point of these systems? To stop someone from breaking in? Wouldn't more secure locks do a better job of that?
I agree. Alarm systems are mostly a deterrent to amateur burglars who probably pick random targets and would likely get frightened off by the sound of an alarm. Particularly if you are gone on vacation, good to know some loud alarm sound will scare off the amateurs. Also depends on what you are trying to protect and need a system that meets those requirements. Apparently amateurs can also be discouraged by having those security signs in your yard or on windows. Alarm systems by themselves don't actually prevent someone from gaining access to your property, it is more about peace of mind. Protecting valuables from pros is a bigger deal, but likely you would want the alarm company experts to advise you on what they recommend. Home alarms are not a one size fits all solution.
Some other common sense things you can do when away on vacation is stop the newspaper delivery (so they don't pile up in the driveway signaling an empty house) and have lights on timers to make the house appear occupied. People often leave windows unlocked that provide an easy access for even the amateurs. First floor windows should always be locked at night or anytime you will be gone on vacation. There are obvious things such as that anyone can do with/without an alarm system to reduce the risk of bugulary.