Someone could have burned down your house. Data could have been corrupted for any unrelated reason. Any physical storage could be confiscated by law enforcement for any reason (maybe there is incriminating evidence against them).
There are LOTS of reasons why you'd want redundant off-site backup.
Those caveats are still enough for me to want on-premises storage for my cameras. Your examples honestly seem like unlikely edge cases compared to wholesale privacy intrusion by data center hacks or Ring just deciding to give your footage to police. It shouldn't even be possible for Ring to share images/videos from your camera if it were designed correctly.
There are LOTS of reasons why you'd want redundant off-site backup.