One of the most important attributes of a good network, ironically, is that it's hard to measure. That means it actually has some serious degree of decentralization and privacy.

We have trouble measuring Lightning, and we have trouble measuring Nostr. This is a feature.

At best we can establish lower bound estimates by observing a subset of the network in question. And since it's possible to run isolated networks with the same protocol for these systems, there isn't even necessarily one Nostr network and there isn't even necessarily one Lightning network, even though there are majority networks for each of them.

Powerful tools.