> they are useful in practice
Useful, yes, but ad-hoc.
> What do you mean by ad-hoc?
I mean that in Emacs you have one ready to use action for everything you might want to do. One shortcut covers exactly one use case; if you want more use cases covered, install plugins or write scripts. M-q is an example, it formats the current paragraph. What if I want to format something other that a paragraph? In Emacs, you will need a new shortcut and a new keybinding for that.
In Vim-like editors you have some small atomic terms that you can combine to build the actions. You can have a small number of atomic terms, which can be combined in a multitude of ways and therefore cover a multitude of use cases. In Vim the gqap is not a single take it or leave it action, it's a sentence with verb gq and noun ap. If you want the verb to act on something different, you replace the ap part with something else.
Think of keybindings as a language you speak to your editor. In Vim the language has a number of words that you can combine to build sentences. In Emacs you have only a given number of ready to use sentences, and you have to memorize each one. This is a big distinction if we're talking about a text editor for efficiency, because it defines the ratio “time spent customizing” / “time saved editing”.
> Could you point me to some example?
You can cut and paste columns in Markdown tables using Kakoune's multiple selections. Like this:
- <a-i>p -- select the paragraph
- <a-s><a-;>; -- this creates a cursor at the beginning of each line
- <a-f>| -- move cursor to the next pipe symbol (selecting everything as it moves)
- <a-.> -- repeat the last move command (do this to select the column you want)
- d -- delete the selected (by each of the selection)
- <a-f>| (or <a-b>|) -- again to move cursors where you want to paste things
- p -- paste the deleted column
In this example, I haven't used a single command that I don't normally use while editing, say, Rust or Haskell. And you can manipulate Org, Latex tables with similar commands. In Emacs, you'd need a separate plugin for each of these, wouldn't you?
Kakoune.org has more videos where they show what it can do (without plugins).