I have used many popular and some esoteric editors and IDEs (some of them today would be considered forgotten). The last one was IntelliJ that I used very extensively. To the point of finding some undocumented features. I have participated in many conversations regarding plugins. I have almost started building my own. I was pleased with it. JetBrains does make an incredibly powerful IDEs.
After almost seven years of using IntelliJ, I switched to Emacs.
Emacs taught me something about myself that no other editor/IDE done before. It helped me to discover my hidden predilection. I realized that I am a tinkerer. You may say: "Aren't we all? We make software because we are tinkerers..." But there are two kinds of developers: non-conformist tinkerers and consumer-tinkerers.
People who end up using Emacs are those who would choose Gentoo or Arch, first of all, because "fuck Windows" and "Ubuntu is lame", and then because they can do some crazy stuff like hijacking display brightness beyond default limits (because one time they had to stare at it, sitting on a beach). Sometimes they hook up their garage doors to a DB, so they can collect data and analyze it later. Or they build their own mechanical keyboards. Etc.
Emacs taught me to abhor repetition and mundane tasks. It taught me that anything can be automated. Even Hell and Chaos can be automated. In that case, you simply end up having an automated hell and chaos. There are so many tiny examples, like whenever I'm writing something let's say in Python, and I would like to search for a code snippet on GitHub, I would simply select a piece of code in my editor and search for it - Emacs would navigate to GitHub, pass the string and even set the language to Python. Or whenever I need to create a new branch, I don't need to think about the name, I can use the ticket number and Emacs would request the issue tracker and create a branch name based on ticket's title. Or I can create a Gist (public or private) by pressing a couple of keys. And many, many more.
I can watch anyone using their favorite IDE and whenever they do something so trivial, something they've been doing for a long time, and very often I'd think - "Oh, I know, more efficient way of doing the same thing" or "Ah, I've been doing it the same way for years, maybe it's time to improve it. I just realized that this is not efficient enough." But it's not just about efficiency - when you add a tiny bit of automation to your task, it becomes so much less frustrating.
Of course, it is possible to have the same mindset and never get into Emacs. However, Emacs offers hundreds of tiny pieces to satisfy your needs. People say: "Emacs takes a long time to learn", but in reality - it would take you longer to become a true power-tinkerer using any other ecosystem of tools.
But it is also totally okay not to be a power-tinkerer. I know many developers who don't use any fancy ways of doing things, but they are still quite impressively, very productive.