One of my favorite quote's from
https://www.gnu.org/fun/jokes/ed-msg.html
"Ed is for those who can remember what they are working on."
But Seriously!
My 2 cents
Ed facilitates and enhances the ability of one to "focus" on the "line" of code they are working on!
Back in the day - When ANSI certifying Power Plant Simulation Code Response to a multitude of failure testing, I thought Ed was superb for that purpose.
(That was 25-30 yrs ago, don't know or care what they use today)