> There's no obligation to always make software useful for other people.

The problem, which you basically acknowledge, is that software that isn't useful generally doesn't get used. If you write nice custom scripts to make your own workflows more efficient, that's great... for you. But to make any interface "useful" (whether it's a UI, an API, etc.), it doesn't just need to be "useful", it also has to be accessible. That should help explain why even crappy UIs are so ubiquitous. They are moderately useful, but extremely accessible.