I use email for anything where you need a document trail, and for communications that can lead to a resolution in one or two rounds of messages. I use phone calls, IM, a handwritten note, leaving documents on someone's chair, or face-to-face for anything else. "Anything else" includes most things that matter. For example, giving feedback via email is generally not optimal.
The ancient Greeks taught their ambitious young men (not women, those were even more sexist times than we're in now) logic and rhetoric. Both were necessary in order to be effective. I learned to be more persuasive and more effective at emotionally engaging with my coworkers and customers because people are not solely motivated by logic when making decisions. Even people who regard themselves as entirely rational.

