Similarly, in Firefox (and maybe other browsers) you can add keywords to bookmarks, meaning that the browser will open that bookmark if you first type the keyword. It will also then insert anything else you type into the bookmarked URL if it has a %s. So as an alternative, more reliable way to search MDN, I bookmarked this:
The benefit to bookmarks / keywords is flexibility and not having to wait for DDG to add (or fix) a given bang search.
The downside is that you're speaking your own language, and unless someone adopts your specific keywords, you can't tell them to, say, "bang dict" (if you can get away with saying that in the context).
This is a fundamental distinction between any private vs. shared language.
(People are very uncomfortable when dropped into my computing environment --- GUI, shells, editors, browsers, etc. They've all acquired several decades of personalisation. Works for me.)
If I'm browsing and need to look something up, I just hit CTRL+L followed by
... and off we go