Interesting study, but this totally falls under Betteridge's law of headlines. No, influencers aren't overrated.

There is no way in hell I will get the message across as effectively as if I have an influencer spread it. This should not even be a question. If I have a story and I tell it to 7 people at random and convince them to spread it vs. convince Paul Graham to spread it - no contest.

We just did a test with one influencer (6M followers on Twitter) to promote our products - bang for buck way better than advertising.

The connection asymmetry (good influencer has magnitudes more connection) and trust/influence (I trust/believe information coming from PG) are important. It is however hard work finding good influencers, and just having a lot of followers does not mean a thing if they are not engaged etc... But worth it.