I bind my CAPSLOCK to ECAPE that way instead of the escape key killing my hand my left pinky finger can just naturally get me out of insert mode by hitting CAPSLOCK.
Whenever I resume a Vim session (from another window/terminal), I have a habit of automatically pressing the (Escape) key to ensure I'm in Normal mode. However, every now and again, I have to use Vim on someone else's computer and muscle memory would cause me to press CapsLock instead of Escape. Then pressing 'h' moves the cursor all the way to the top of the screen instead of one space to the left, pressing 'j' joins the current line to the following one instead of moving the cursor, etc. Because I'm used to typing normal mode keys in quick succession, I've already entered 4 or 5 normal commands before I realise it's all going horribly wrong. I press 'u' a few times to undo the craziness but successive presses of 'U' only undoes the previous Undo action!
In the end, I retrained myself to use Ctrl-[ which isn't quite as convenient but does work on all platforms I've had to use.
caps+(any other key) mapped to ctrl-shift-command-option+that key(useful to bind to extra shortcuts in an app).
a single just caps lock press alone bound to escape.
and finally right shift + caps lock is bound to toggle caps lock on and off.
works pretty well for me for a long while now.
karabiner elements on macos lets you do all that with "complex modifications" though the config is a bit dumb to do manually as they expect you to download configs from the web.
A side benefit of this is that F5 is mapped to refresh for a lot of apps (Firefox, for one) so I can hit capslock to refresh a page.