(other user) in my typical experience:

- keyboard can be used for pretty much everything

- less visually busy (no/less animations, background images/color variations. often close to plain text on plain background)

- more information dense (fewer things hidden behind hamburger menus, modals, drawers, etc)

- more/more easily customizable and documented

- more often can provide data directly into the terminal that I'm working in, so don't need to copy/paste through windows etc

these aren't necessarily impossible for GUI or universally true for TUI, but maybe I would guess just more an artifact of there being types of people who prefer working in the terminal who are then more likely to make TUIs, and I share their preferences more.