Imagine instead of pressing backspace to delete a character, you would have to delete the individual bits that make up the character. A character is just an abstraction of bits, that your text editor/IDE takes care of for you so you don't have to think about it.
Vim is also an abstraction, making it similarly far more convenient than doing everything by hand. Think about it: Is "forward 2, backspace 5" or "delete this word" a more natural abstraction?
So what's the advantage? Speed, but not typing speed. It's about the mental distance between the model in your head of what you want to happen (delete everything between the parens) and the model your tool understands (go forward some words, go forward 1, delete backwards 20). Since speed = distance per time, reducing the mental distance increases mental speed.
And that therefore uses less mental energy on translating for your tool, and leaves more room for doing hard mental problems, like fixing a bug.
But, since you mention it, there are a few things that appeal about vim. For me, personally, I am quite often working on remote systems from the command line. Being able to "vi filename" and make some changes and get back to the command line is important and VSCode doesn't seem to work for that. I know it has remote editing, but navigating over there from Code isn't worth it when I can just "vi filename".
A significant part of the appeal is the modal editing, which as I mention above is available in Code.
This combined with the excellent text manipulation features right there from the keyboard, without leaving to menus, being able to just flow with the Vim -keybindings, and in all different IDEs and editors that support Vim -support, it's just great.
All these people who claim the keyboard is so much faster than the mouse (instead of a combination of both, as I claim), are people who never played StarCraft.
Select from this point to the parenthesis? I can see the parenthesis, and I can do the mouse select as fast as they can with their keys.
The use of four keys to move the cursor? I can use the cursor keys the same way, they work in all programs, and I have used them so much for many years that I don't need to see the keyboard either. I move the hand and the keys are where I know they are. And they are familiar, and I can use any keyboard in any normal computer as well.
So, my point is: muscle memory helps, a lot. Vim doesn't have a monopoly on muscle memory.
But when you just want to fire an editor to do a quick change, vim is your friend. It’s also reliably present on almost any server you’ll ssh into
(Full disclosure- I never write JavaScript).