Emacs

First I wouldn't concern myself too much with trying to explain what differentiates Emacs from an IDE. Life is too short to get into such debates. I can't really summarize why anyone should care about Emacs vs their IDE of choice.

For me what separates Emacs from vscode for instance is not the IDE aspects but the integration with the broader ecosystem. I'm a PM that works with technical and data heavy products. The details matter. I frequently walk through the pipelines and code of my product to understand how it is implemented by the team(s).

For example you can break my underlying product down into 3-4 large blocks of pipelines. Each pieline has 6-7 stages that mix Spark and other Python jobs. For each pipeline and stage I have my own little literate org file that points to code, has small samples of inputs and outputs, and generally speaking allows a non data engineering professional such as myself keep up with people that are far better and keeping this all in their head.

I write down questions as I do this to browse and/or raise with the team. I can, when questioned by our senior leadership, truly explain what it is our team did and the impact it had.

I can't do that with an IDE. I can't see an easy way to do that with any of the other note taking tools. I can't jump between code browsing, executing and writing as seamlessly anywhere else.