It would be a good way to measure popularity/influence. It doesn’t mean they are legit. You can be an impersonator/scammer and have a lot of followers.
Discussion
Lots of followers alone wouldn’t help. People you follow would also have to follow them. The odds of that are pretty low imo.
Lower, yes, but it’s not foolproof and could contribute to someone getting scammed if Damus starts advertising it as a quasi security feature. What if all your “friends” follow an impersonator account because they realize it’s satire and find it funny, but you you’re not in on the joke? However, it could be that I’m missing a key concept. I still don’t understand all the basics of the Nostr protocol.