It's where I write all of my personal notes, blog posts, and it's where I wrote both "Game Programming Patterns" and "Crafting Interpreters".
At the same time, it's not the tool I use as an IDE. For programming, I use whatever IDE is dominant for the language I'm working in. Over time, that's been Visual C++, Visual Studio, XCode, Eclipse, IntelliJ, and most recently VS Code.
That doesn't mean to me that I want Sublime to turn into an IDE. I like that it's lighterweight than that. It's the perfect sweet spot for me of rich enough to handle piles of notes and documents and small scale code editing, but not so huge and cumbersome that it gets in my way.
Are people just working on more complex software than I am so you need the build steps hidden behind a UX, or am I missing some killer IDE feature that I don't even know about?
EDIT: It probably helps that I'm a vim die-hard and couldn't imagine clicking on something to rebuild the program! And Sublime's Vim support is better than any real vim program I've ever used, much less the half-hearted versions available in the IDEs I've tried. Maybe that's the main disconnect, and y'all just prefer having dropdown menus?
Many years ago I saw an advertisement about some cooking tool. This old East Asian grandma, ninja grandma looking, was doing some prep work for some dish. She stops, looks in disgust at the tool she was using and says "this is meant to bring joy, but this is not bringing any joy". She then switched to the "better" tool and all was good with the universe and much joy for everyone.
This is why I use the tools I use, because they bring me joy. There is an argument to be made that I use some of my tools because they bring me less sadness, but oh well.
I use vscode because it brings me joy, nevermind that I use less than 10% of its capabilities (eyeballing). I compile, run tests, use source control in Windows Terminal, because Windows Terminal brings me more joy than the vscode terminal.
I use a cage on my photo camera because it brings me joy. I use a Peak Design sling because it brings me joy. I use my Lowepro sling bag, that I got as a bonus after buying a cheapish tripod, because it brings me joy. The next version of my bag, size wise, it's a proper backpack, now I'm planning to get one and see how the joy levels are.
You use whatever you use because that brings you joy. You can try and rationalize this in any way you want, at the end of the day, the amount of joy is the only real reason you use what you use. Whatever we use doesn't make us better or worse, it makes us human.