I am this very term teaching 18-year-old students 6502 assembly programming using an emulated Apple II Plus. They've had intro to Python, data structures, and OO programming courses using a modern programming environment.

Now, they are programming a chip from the seventies using an editor/assembler that was written in 1983 and has a line editor, not a full-screen one.

We had a total of 10 hours of class + lab where I taught them about assembly language and told them about the registers, instructions, and addressing modes of the chip, memory map and monitor routines of the Apple, and after that we went and wrote a few programs together, mostly using the low-resolution graphics mode (40x40): a drawing program, a bouncing ball, culminating in hand-rolled sprites with simple collision detection.

Their assignment is to write a simple program (I suggested a low-res game like Snake or Tetris but they can do whatever they want provided they tell me about it and I okay it), demo their program, and then explain to the class how it works.

At first they hated the line editor. But then a very interesting thing happened. They started thinking about their code before writing it. Planning. Discussing things in advance. Everything we told them they should do before coding in previous classes, but they didn't do because a powerful editor was right there so why not use it?...

And then they started to get used to the line editor. They told me they didn't need to really see the code on the screen, it was in their head.

They will of course go back to modern tools after class is finished, but I think it's good for them to have this kind of experience.