But why someone would intentionally make things more difficult for themselves as a preference, I don't get. It would be like walking around in crutches when you have two perfectly healthy legs.
As a more common example, I only launch applications by opening a prompt (e.g. Spotlight on Mac) and typing the first couple letters of the program I’m starting. This is much faster than navigating using the mouse to the applications folder/menu/dock/taskbar etc. and clicking an icon.
I agree keyboard-based navigation is not faster for everything. Luckily, tools like this don’t prevent you from also using a mouse!
There are times when a mouse is good, there are times when I don't want to take my hands off the keyboard and mouse for something.
No-one would do that, that would be crazy. People intentionally make things easier for themselves as a preference, and different people find different things easy or hard.
So it's less like crutches and more like rollerblades.