Why this is preferable? I would rather have the apps I use represented as a list of apps in my system (drawing on a couple of decades of established UX conventions for how they are displayed and how I can interact with them), the web content I'm reading represented as tabs in my browser, and my terminal sessions represented in my terminal. You present the destruction of this simple separation of concerns as a benefit, but don't explain why it is one.

If age of conventions is a valuable metric, TUIs have way more. The keyboard hasn't change noticeably, and I can work way faster between separate windows/panes in a terminal and tmux, than in various GUI windows, where mouse focus dictates when I can start inputting.

While a mouse can theoretically use all pixels of a screen, in practical terms a keyboard has a way larger input space than a mouse, and if I can keep both my hands on the keyboard, I can work much faster.

At least that's my experience as a (starting) greybeard.