Using a CA instead of proof-of-work, I could see the underlying concept being useful in chain-of-custody type applications or limiting the attack surface of a compromised server.
I think this word is now like "hacker" or "AI". It's not completely meaningless -- it does have a kinda-sorta fuzzy meaning. But that meaning is different from what techincal experts mean when using the term and is very much audience dependent.
Using digital signatures in a chain is not a novel idea. Without PoW you do not need the block part, just records.