Most UI library store states in tree of components. And if you’re creating a custom widget, they will give you a 2D context for the drawing operations. Using react makes sense in those cases because what you’re diffing is state, then the UI library will render as usual, which will usually be done via compositing.

The terminal does not have a render phase (or an update state phase). You either refresh the whole screen (flickering) or control where to update manually (custom engine, may flicker locally). But any updates are sequential (moving the cursor and then sending what to be displayed), not at once like 2D pixel rendering does.

So most TUI only updates when there’s an event to do so or at a frequency much lower than 60fps. This is why top and htop have a setting for that. And why other TUI software propose a keybind to refresh and reset their rendering engines.