For VIM development check out ctags (or LSP) with auto complete. It's magic for large projects.

For me, its the massive range of editting manipulation it provides, and the reduction of dependence on using a mouse. For context, I have some level of wrist injury, so my complaints around mouse usage mostly stem from that.

I would love to explain in detail what makes Vim great, but I think noboilerplate on youtube did it best with this video: https://youtu.be/sqm4-B07LsE

But if I had to explain one of my favorite parts of vim, its the fact that I keep finding new solutions to improve my ability to edit code with an ease I had never felt before. Using 'vf' in order to easily highlight from where my cursor is to whatever character I want to get to has saved me so much time when rewriting variables or cleaning up code. Ive barely learned about what EX mode can do, but being a lot of work involves correcting other code or duplicating it for use with a different part of the code base, being able to use the substring command is drastically more helpful than your standard ctrl+H will do. Easy example :.,+5s/foo/bar/g Colon is what puts you in EX mode. Period is the current line, comma indicates this is a range, +5 means the next five lines, s means substring which is the command that we are using. "foo" is the word to search for, "bar" is what "foo" will be replaced with, and g means to replace all instances. Drastically more robust and useful than what ctrl+H does.

Vim just makes it easier to manipulate text. Its drastically reduced strain on my wrists, and puts me in a flow state far more often than I ever experienced before I used it. Its kind of like aiming in a first person shooter with a mouse instead of an analog stick. Both will get the job done, but a mouse is drastically more capable at being accurate. Thats what vim feels like for coding for me.