PGP public keys you can also just copy around? Nobody is forcing you to use the web of trust with PGP either, if you don't want it. But if you do use keys extensively, it actually helps you: if your boss already verified a customer key, you don't have to re-do the work and meet up in person or ask your boss to send it over before you can use it. Now extend that to a whole network of colleagues, where you configure per-colleague whether you think they properly verify other people's keys, and this whole key distribution problem becomes a lot easier without having to rely on third parties (CA system like with https).
Just a small note, this obviously doesn't invalidate the rest of the article!