“It’s been a lifesaver in those cases when I didn’t really mean to highlight the whole page before hitting the delete key. “
Back in the day, if I made such an error, the cure was to ctrl-?(don’t remember) and ‘crash out’ of the editor.
Then edit the change file of keystrokes to take out the last few.
Then re-edit, applying the edited change file, which would re-edit, without the last few offending keystrokes.
These days that is considered ‘geeky’.
Today's computer users are spoiled with "user-friendly" displays and buttons to push.
In the olden days, with state-of-the-art "dumb" terminals such as HP 2645s, you had to know the keyboard shortcuts to do anything worthwhile.
It didn't take me long to learn Ctrl-S to stop the screen from scrolling. Otherwise (in VMS) the "ty" command displayed everything from beginning to end of the file you were hoping to examine. And once the page scrolled past, you couldn't go back to see what you'd missed.