I think valuing how easy it is to learn over efficiency is not the best option: learning even a difficult text editor takes a constant and reasonably small amount of time. Being more efficient is a benefit proportional to how much you use the editor. So anybody planning to program for a long time is probably going to be well served by learning a more efficient but "harder" editor.
Now, in the real world there are other considerations and the question is more complicated with regards to actual editors. However, given a hypothetical choice between something harder to learn but more efficient or easier to learn but less efficient I'd go for the former each time.
This whole talk of efficiency surprises me. if that is what we are looking for, then in my mind you are either writing too much code or aren't thinking the problem through. In my experience, coding takes up less time because you get better at it.
Efficiency isn't really about entering text, it's about quickly navigating around large amounts of text, editing parts, performing larger operations, integrating the rest of your workflow (maybe a REPL or a browser preview or tests...), testing code, exploratory programming, combining different languages, working with markup languages (HTML, XML, Markdown, LaTeX), writing documentation, reading documentation...etc. The beauty of Emacs is that it does all this (and more :)) well for a whole range of languages.
The goal is not just to be able to do anything you need quickly, but to do it in a way that doesn't break your concentration and doesn't take much thought. Moreover, this has to apply to pretty much every sort of thing you do with your source files, which is actually quite a lot. Today, almost any work you do on your software project as a developer involves text, not just programming, so efficiency really matters.
Additionally, it should be really easy to create complicated workflows for your specific project. For example, I am working on some code that operates on two trees and produces a third. It literally took me half and hour to create an Emacs command that took some (configurable) input, ran my function on it, rendered the result with LaTeX (using a tree-drawing package) and displayed it. This way, when I make an edit to the algorithm, I just run a single command and see the output immediately with a nice visualization. This makes playing around with modifications to the algorithm very simple.
Now, in the real world there are other considerations and the question is more complicated with regards to actual editors. However, given a hypothetical choice between something harder to learn but more efficient or easier to learn but less efficient I'd go for the former each time.