[asddubs]

I would seriously not recommend doing this, because it's terrible at communicating intent. Yes, it works, but someone else (if you're lucky) or you will be staring at a variable that seems to have come out of nowhere trying to figure out what's going on sooner or later. Especially if the HTML id inadvertently got changed without changing the variable in kind

[chrismorgan]

The spec appropriately points out that this is a fragile technique.

Also to avoid any doubt: if something’s called a golfing trick, you almost certainly shouldn’t use it on normal code.

I confess I use this technique on every page on my website, in my carefully-golfed light/dark mode switcher. (https://chrismorgan.info/blog/dark-theme-implementation/ has a slightly-expanded version of it, and uses a more sensible document.querySelector instead.)

[orangepanda]

It's great for quickly fiddling around in the dev console.

Similarly - $0 gives access to currently selected element

[asddubs]

sure, for throwaway code anything goes of course