Force of habit... I'm not really sure how I made the move, I grew up on Macs but moved to Linux (for the FREEDOM), and gradually all the GUI apps just fell away. I have a PDF reader and a browser and I think everything else is in the terminal. Occasionally I'm forced to use a Mac or Windows machine in professional situations, and it just annoys the fork out of me. I just prefer typing, and I have all the commands I need memorized to an embarrassing degree.
I also appreciate the resource usage. My personal laptop is a Lenovo from 2009, and it never feels slow. It is slow for some things, like compilation, but it never feels laggy in the way a GUI can.
I would never recommend to anyone that they go down this road. It's silly to think how many hours I spent learning what I know, and the main effect is that nobody but me can use my computer and I barely know how to work anyone else's. I'm wicked fast on VIM and that looks cool and all but... the bells and whistles in something like VS Code probably help more in the day-to-day as a developer. But I can't use it. I feel completely lost when I can't Control-Z and git grep, or whatever. I don't even know how to quit a GUI programme anymore.