Car alarms are similar. Maybe (but doubtfully) they'll prevent your car from being stolen/trashed/emptied. But at the cost of waking up an entire neighbourhood every time a bird shits on it a little too forcefully (or whatever it is that randomly sets off car alarms in the middle of the night). That's not a tradeoff that works for me.

Your house is on fire? Fine, wake up the whole neighbourhood. You're in physical danger? Sure, emergency services can be as noisy as they need to be. Some of your stuff is in danger of being stolen? Meh, I don't want to get out of bed for that.