My eyes glazed over reading that. I feel like 30 years of internet has proven one thing: the simplest solution always wins. PGP is many things, but simple and obvious are not among them.
Depends what you do, and if your organization has a persistent clown infestation. Some big business folks still use email as a human to API interface.
Running out-of-band public keychains is not something most people will ever need. =3