Modal editors in particular can be a mixed bag, they do seem a little out of place in the world of IDEs and Visual Studio Code, but I'd be lying if I said I don't use them heavily. The main appeal for something like this is to keep your hands on the keyboard so you can focus on writing.

> Why some devs try to avoid the mouse?

Because a keyboard is a much better peripheral to use when you're SSHing into your server. A mouse also has a much higher latency ceiling to execute most commands because it requires much more spacial awareness and brainpower to perform the task than just invoking the keybind. When you move your mouse to hover over a "send" button on an email client, your body is performing subconscious inverse kinematics to try to figure out how far to push the mouse, and when to stop. You can then only click once your mouse successfully lands in the designated area, at which point an additional 50-500ms of latency will ensue, depending on what UI framework your text editor is based off of.