If we're considering the adversaries here as both a centralized provider for recording access and storage, and the intruder who might look for a DVR and destroy it, then it's reasonable to want a way to decentralize all copies of the data and also not want untrusted individuals from having access to the decentralized copies. The argument GP provided wasn't that off-site storage was bad, but that off-site storage in a SaaS platform that is easily identified as a destination to subpoena by virtue of seeing the Ring brandname on the doorbell and/or cameras is risky and in their opinion undesirable.