You're clueless and missing the point.
While YOU may need the credits, it is considered a gear piece first which is intended to be used.
Any usability of that item trumps your need for credits. Regardless if it is for a companion, DPS/TANK set, alt, or just rolling for mods. There are many different dynamics to this game with the advent of companions. I said earlier, companions are more important to some AC's then others. Who are you to determine what item should be sold for credits?
Give me one AC where a companion is not needed. And if you are a tank and you aren't using your healer companion then you obviously don't know squat about how to play.