The editor has key equivalents for all the buttons (Ctrl+B for bold, etc.). However, the most annoying thing to type is
<kbd></kbd>, but there's no key equivalent for this. Can haz?
There's a userscript for this. It adds a keyboard shortcut (AltK), and a kbd button like this:
Update: The script now also adds a few other useful markdown shortcuts as well. See the post about the script at Stack Apps.
Directly install it from GitHub. (Requires Tampermonkey, or Violentmonkey, or equivalent.)
If every possible feature had an associated UI button to do the same thing, then there would be a stronger and stronger precedent to always have a UI button to do every little editing task. Then it would be impossible to add a new feature without also adding a new UI button. This is a fast track to a cluttered, unusable UI.
Also, people have been successfully training their fingers to type open-close HTML tags for twenty years. Get used to it.
Adding a keyboard shortcut would probably also include making people aware of its existence? Or make people who already knew about
<kbd> use it more often? Please, no, don't increase using
(The formatting only looks acceptable to me on the Apple site. But even there it's not really needed, I feel. On all other sites: ugly, and hence, for me, annoying. As an aside: I see abuse of irrelevant inline tags too. Like here. I rarely see a true need for