Notepad is heavily used as an IDE (Integrated Development Environment) by a lot of people. It's not exactly a good development environment but it is nonetheless. I would actually argue Notepad is used primarily by programmers, and that casual Windows Notepad users are in the extreme minority. The whole reason it's so heavily used is because unlike WordPad or Word, it doesn't include formatting data, which can fuck up computer code.
Notepad++ for example is literally built to be more like an actual IDE and supports color-schemes and indentations for numerous computer programming languages.
Microsoft isn't entirely stupid (just mostly), and in knowing this, they're pushing to put their programming Copilot where they think it needs to be: Inside IDEs, which to them includes Notepad.
Notepad is definitionally not an IDE. It is not an integrated environment -- and anyone who is intentionally using it over alternatives is almost certainly doing so precisely because they do not want their text editor to be an integrated environment.
I'm sure there's some case where Notepad is PART of an integrated environment, but it would have to be with support of other tools -- likely a terminal of some sort.
The reason other text editors like -- like Notepad++ or Neovim -- can be full IDEs is because they have plugins to generate that integrated experience.
Notepad isn't "technically" not an IDE. It does not have any of the features that make an IDE an IDE. People using something for programming does not make that thing an IDE.
An IDE is an integrated environment for development. Notepad is not integrated with any environment. That's what makes it good.
Saying notepad is an IDE is like saying a wheel is a car. While yes, a car uses a bunch of wheels and you can get movement by using a wheel, a wheel is not a car.
Yes, IDE's involve text editing. And yes, you can code in any text editor that outputs a correct file format. But that doesn't make every text editor an IDE.
It's not tomato:tomAhto. It's more like tomato:pizza.
Notepad is used by anyone who wants to see what is actually in a text file.
It's used a lot for stuff where data is transferred in a text format. Comma separated files etc. are still widely used for transferring data flawlessly without having to convert types or mapping a document standard or whatever method that could potentially fuck up or just take more time.
It's simple and it works.
F.i if you open a file in excel or word, change one character and then save, you can bet that the entire file is fucked up afterwards, because those programs don't show the data directly. The moment you open it, it might very well be fucked up just from that.
If you transfer a file by some kind of JSON format, which is all the rage currently you'll have to map it from both ends, and it also begs the question: Why are we doing running all this code just to transfer one byte?
The beauty of text files is that it's (almost) raw data. (Only "almost" because there are still different localization standards that can fuck up even a text file.)
Notepad covers that. Of course we could use other apps for viewing data, but most of the time, it actually is text and not hexidemal codes or whatever you can save in bytes.
Programming wise, the only thing I use notepad for is making DOS batch files. Again, because it's raw text and should be created and read as such. No parsing, no compiling. Just text.
I'll also use it for storing data for programs, because it's easy and raw.
For actual programs, it'd be better to get Notepad++ or MS visual studio code, which at least will highlight commands and collapse functions etc.
And still, these also aren't actually IDEs, because they don't compile the code (unless you get those add-ins).
We could also use those for text files as well, but it's overkill. I don't really want to open an app to view data. Notepad is small and quick and not bloated with features, which is ideal for whenever I only want to see what's in the file.
The original MS Paint was similar for pictures. They fucked that up real good. Its been..14 years and I haven't really gotten over how bad it is. It used to be pixel perfect and logical, but now you can't even save a file with transparency, but hey here's s brush with stroke width and blur that'll make sure you can't edit a single pixel. Way to go Microsoft.
If they do the same to Notepad, I'll have to resign my job, because it's not going to work like that.