I think detecting whether stdin is a TTY is a huge antipattern. Most of the time, it works, but now and then, you either want to run an interactive session in a situation where stdin appears not to be a TTY, or a batch session in a situation where it appears to be. Plus, it means there's twice as much surface area to learn.
> you either want to run an interactive session in a situation where stdin appears not to be a TTY
Um... why? That is literally the situation for which the pseudotty device was created.
There is a spectrum between "interactive" and "scripted" utilities, and the command line interfaces we're talking about sit balanced on the interface. There's no way to make everyone happy, more or less by definition. So I think "huge antipattern" is maybe spinning a bit too hard.
You get false positives sometimes (where it claims to not be a tty but is going to the screen), but because the fall back is just reduced functionality it never causes any issues. We make hundreds of checks like this for tty in the CLI
EDIT: remove rogue 'not'