When a program clearly deviates from its spec, would you be okay with calling that a "bug"?
There's always a gray area of what's intended by the spec, but a program can absolutely and blatantly deviate from the letter of the spec, and they often do.
This distinction seems worthwhile to me, because it means that something someone already relies on does not work (anymore), even though reasonable people would agree that, according to the spec, it should.
Absolutely would. But if we can categorize 1/3 of defects as ”bugs” 1/3 as ”missing or incomplete functionality” then there is 1/3 in the middle which we can’t decide. So the dichotomy is kind of weird, and making ”rules” and processes about this categorization is probably not worthwhile.
At least not worthwile for the purpose you have in mind. Okay, now I understand better what you mean, something like: for some purposes, there's not much to be gained by distinguishing between "bug" and "feature", one major reason being that there is no clear boundary between the two.
I first read your original comment in a much more absolute way (there is no distinction at all, and it never makes any sense anyway), which is quite easy to disagree with.