"
The proof-of-work chain is a solution to the Byzantine Generals' Problem.
...
The proof-of-work chain is how all the synchronisation, distributed database and global view problems you've asked about are solved.
"
- Satoshi
https://www.metzdowd.com/pipermail/cryptography/2008-November/014849.html
Proof-of-work is /the/ honest signal in the electronic network medium.
An honest signal is a signal that reliably imposed a cost on the sender.
Our societies are struggling at the moment with this unfortunate combination:
1) Our business and social lives are moving onto the Internet, due to the lack of friction of communication, which makes it cheaper than the alternatives.
2) Our ability to send honest signals via the Internet is diminishing due to this lack of friction, and also due to the use of AI to generate fake signals.
Ideally, we'd use proof-of-work to handle the problem of "proof-of-human". I.e. a reputation tree system, regularly timestamped on the Bitcoin blockchain.