The little surprise is worth the general improvement in usability (e.g. colors, progress bars, filenames you can copy&paste, terminal not getting corrupted by escape sequences, etc). It also makes it clear that the terminal output is for user interaction, so programs no longer have to be both UI and API at the same time, they can focus on one or the other, making both much better and cleaner as a result.
> ...then you run the result through sort and trying to avoid the header...
The much more common scenario would be doing `foo | sort` and then ending up with random header text in the sorted data. Few people will add a `tail` the first time they type that command or remember do it every time they use it interactively. With `isatty()` it behaves as the user expects it right from the start.
> ...then you run the result through sort and trying to avoid the header...
The much more common scenario would be doing `foo | sort` and then ending up with random header text in the sorted data. Few people will add a `tail` the first time they type that command or remember do it every time they use it interactively. With `isatty()` it behaves as the user expects it right from the start.