In effect, you're telling me you are willing to trust every/any phone to self sign a video and upload it into the block chain as truth?
So as a bad actor, I'll just take a video of a deep fake video with my self signing phone to circumvent your trust?
Ah but it's easy to spot a video of a video!
But what if I just replace the camera with a direct feed system?
That's absurd amount of money/work, why would you do that?
Because I'm a state level actor and I really want this war to start.
BTC & Eth are trustworthy because the original pool we can perform tests against the math which it is built upon. In fact, it doesn't matter who uploaded BTC/Eth. The system is a self contained math problem.
An uploaded video does not have such self-testing ability because it always comes down to "who" took it and who uploaded it.
"Trust at the source" or "Who to trust?" is now the problem. Blockchain cannot solve that alone. I don't know any system that could.