Mice + keyboards are good for versatility. When you need more than data entry or non-tabular (images, video) data entry or processing, having a mouse is key.

A mouse is not itself a problem, although most functions should be operable by keyboard. When selecting objects and points on the screen, the mouse is helpful. It is best to have both, although I would think that a keyboard alone is generally better than a mouse alone.

You're 100% correct. Keyboard is not better than mouse, both are good tools which complement each other.

True. I should have qualified that as applying to particular tasks.

https://danluu.com/keyboard-v-mouse/ - "Unlike claims by either keyboard or mouse advocates, when I do experiments myself, the results are mixed. Some tasks are substantially faster if I use the keyboard and some are substantially faster if I use the mouse. Moreover, most of the results are easily predictable (when the results are similar, the prediction is that it would be hard to predict)."

It's part of it but not all of it. Today's modern UIs won't buffer keystrokes as you move between UI contexts. You often have to wait for a bit of UI to load/appear before you can continue, or else your premature keystroke will be eaten or apply to the wrong window. This kills your throughput because you have to look at the screen and wait to recognize something happening. Even if you have all the keystrokes memorized, the UI still makes you wait.

In a traditional TUI you can type at full speed and the system will process the keystrokes as it is able, with no keystrokes being lost. If a keystroke calls up a new screen, then the very next keystroke will apply to that screen. Competent users could be several screens ahead of the computer, because the system doesn't make them wait for the UI to appear before accepting the keystrokes that will apply to that UI.

This works if you have one app with a completely dedicated computer. But that's a limitation on the popular systems. If you have an automatic focus switch to new windows, like Windows/Mac pretty much enforces, you can't buffer input. An incoming call to your VoIP system would be dropped/redirected, because you were typing the right thing at the time.

No, Windows goes out of its way not to allow a popup window from a background application to take focus. Instead, it blinks the taskbar icon. An incoming call should not start eating the keystrokes you were sending to the active application. Focus stealing isn't totally solved as an issue, but it's certainly regarded as a problem to be solved and not the desired behavior.

That's nowhere close to my experience. Things that steal focus constantly: 1password losing SSO token, UAC for an application's backup, 3CX call coming in, every random thing in vscode, ...

It's not something windows does or can disallow. You just focus the window in the code and that's it.

>Competent users could be several screens ahead of the computer

Reminds me of https://en.wikipedia.org/wiki/Therac-25

While I prefer to use a keyboard, it is not true that keyboard are universally faster. Even text navigation can be significantly faster with a mouse if done right, especially if you start to go into button chords.

What works best is heavily task dependent, and also needs to account for cognitive load and training requirements. Stations with few primary tasks taking limited input (e.g., product lookup forms and customer purchase forms) lend themselves heavily to a keyboard driven UI, but many others either do not. In that area, it ends up just being a strong personal preference guiding what seems best.