If nostr implements 2 scores like you mention (global and personal), the personal score will eventually eclipse the global score in power and importance. It’s something that can only be implemented properly in a decentralized system like nostr. Centralized systems are simply unable to provide personal scores for various reasons, which is why we’ve never seen their power unleashed.

A global score is nothing different than a particular personal score that is centered around whoever represents the community. eg when Google calculates PageRank scores for websites, it’s basically a system of “personal” scores, except that the only score we ever see is Larry Page’s (Google’s) “personal” score, and none of the rest of us ever get to see our personal scores. So the global score = Larry’s personal score. And in a broader sense, “global” score always = the “personal” score of an individual or entity.

I wrote years ago about personal vs global scores here:

https://github.com/WebOfTrustInfo/rwot1-sf/blob/master/Principle-of-Relativity-for-WoT.md