Zaps are also a more easily gameable metric without web-of-trust also playing a factor.
I could zap you 10k sats and get you into the trending list, and you can send me back 95% using a standard LN transaction.
An interesting sorting metric could also be a binary “zapped or not” + web of trust. I want to know nostr:npub1qny3tkh0acurzla8x3zy4nhrjz5zd8l9sy9jys09umwng00manysew95gx zapped something because he has high signal, but just because he does giant zaps on the daily doesn’t mean it should overpower 10 people zapping 1 sat.
At least could be an interesting option.