Related to #1 you mentioned, to me Textual looks just ugly - like if someone thought it wasn't enough for desktop GUIs to be infested with mobile phone UIs, it also has to be the terminal apps too.
Like, hell, their examples have some *HUGE* buttons, starting with a calculator app that is all buttons - who is going to click on those? The calculator-with-buttons barely makes sense for desktop GUI apps (it was helpful back in the 80s when everyone had a physical calculator on their desk to help see the metaphor of the "virtual desktop" and it is arguably helpful on touch screen devices today for obvious reasons, but on a machine with a keyboard it is superfluous), let alone TUIs.
If you want to see a TUI that actually looks good (though a bit too much on the fancy side, but it doesn't pretend to be something it isn't) check btop:
What coldtea mentioned, the examples in the site you linked look better (well, most of them, some still use these pointless gigantic buttons). And the thing is every time i see the Textual linked here, it isn't with screens/examples like in the site you linked but with screens/examples like in the official site linked above.
From what i see the screenshots in the site you linked at are from programs made by others instead of Textualize themselves, so perhaps they should take a note of how the people who actually use their library and make TUI applications style their programs and redesign theirs accordingly.
Like, hell, their examples have some *HUGE* buttons, starting with a calculator app that is all buttons - who is going to click on those? The calculator-with-buttons barely makes sense for desktop GUI apps (it was helpful back in the 80s when everyone had a physical calculator on their desk to help see the metaphor of the "virtual desktop" and it is arguably helpful on touch screen devices today for obvious reasons, but on a machine with a keyboard it is superfluous), let alone TUIs.
If you want to see a TUI that actually looks good (though a bit too much on the fancy side, but it doesn't pretend to be something it isn't) check btop:
https://github.com/aristocratos/btop