Most if not all software is shipped with known defects. So clearly, the fact that a "bug" can be identified doesn't give any weight when describing when it need

Most if not all software is shipped with known defects. So clearly, the fact that a "bug" can be identified doesn't give any weight when describing when it needs to be fixed. A missing feature can be just as onerous to a user as a defect. Understanding if an issue gets in the way of productivity is all that matters, regardless if it's described as a bug or a feature. Tracking metrics against bug vs. feature is a surefire way for a system to be gamed. If there are consequences in finding/reporting defects, then all work-items will eventually be labeled as "features". Or if you reward finding bugs, then all work-items will gravitate towards "defects". It's up to you how you want to play this game.