You still have to rely on a middleman (the blockchain), which I believe isn’t infallible either (human input error, adversarial attacks, phishing, social engineering, network availability, etc)
I mean, you could use blockchain for this and create a viable solution. I don't think that's the only solution, or even the best solution in this case, but, worth considering the idea at least.
You still have to rely on a middleman (the blockchain), which I believe isn’t infallible either (human input error, adversarial attacks, phishing, social engineering, network availability, etc)