I used line editors in the mid 80s on old-at-the-time systems. Some editors supported both line and screen modes, but we didn't have the more expensive terminal which would have allowed screen mode (there were a class of glass ttys with no cursor positioning commands available).

It's pretty easy to get used to line editors, you get used to using the search command to position the cursor on the correct line and change command to modify it. Some friendly line editors include DEC's EDI and EDT (PDP-11) and E (Motorola Exorciser).

UNIX ed is nice in that it has has regex support, but I don't like its side effects- that p, l and i change the cursor line.

I had no use for edlin since screen editors were available on the IBM PC.

I tried but never got used to TECO: this is like a screen editor, but no screen: meaning the cursor could be anywhere in the file, including in the middle of a line and it's up to you remember where it is. Some TECOs had a screen mode where it would show you the buffer and cursor position in one window, but accepted normal TECO commands in a separate command window ("TVI" on TOPS-20 worked like this, EMACS was a TECO extension).