What's with the "cloud" security systems? Why don't they just provide hardware where you store the information locally? Ignoring the privacy implications menti

What's with the "cloud" security systems? Why don't they just provide hardware where you store the information locally? Ignoring the privacy implications mentioned here, and that you esentially pay monthly/yearly for storage, if your ISP has an outage your security system is becoming useless. It also is a weak point for smarter thieves (just make sure that Internet access is cut).