The bar example is a still a bit vexing to me, because it's the sort of problem/solution I often see brought up as an example, but I still fail to see the utility. A digital signature (e.g. PGP) already can act as a certificate of authenticity from a trusted party and all you need is their public key. Could you explain what the blockchain improves about that, or what it solves in that application that digital signatures don't already?
That its difficult to do today, you need to manage your own private key infrastructure. So it becomes reserved for a few important things, like a digital ID.
What if it were easy and dirt cheap to make a provable claim about anything, in seconds, with a fraction of the infrastructure cost?
Like "I am signed into this application". Or "I have received a covid vaccine", or "i authorized this payment". Theres probably a lot more, my background is in identity so those are the ones I know.
Yes you can do those today but they all carry significant cost, and as a result there are significant moats around established players.
Just like Letterman asking "why do I need such information, have you heard of magazines?". Its true, magazines can do that. Just like PKI can do all those things.
