Other than possibly having access to rarer skills, are there any other differences between say a green, blue or purple colored Boff to a white one? They seem to be treated like items? Could I technically train the bridge crew I want (say I wanted specific race/officer type combos using the white colored ones you can requisition from vendor) and then wait for the rare officers to shows up in game through drops or whatever and just Train one of my own with their rare skills I need? Do I lose any other advantage by not letting the rare officer join?
Hope that made sense.
EDIT: Oops, nevermind. Just read the big differences are the better space/ground traits for more rare officers.