Important to keep in mind what the MEL is all about .. and that is to permit the intentional despatch with bits and pieces U/S.
It is the intentional aspect that drives the philosophy. With intent it is appropriate to address the basic certification requirements .. eg, for packs, why did we have two for the original certification ? If we launch with one U/S, then what do we need to do in the way of restriction to achieve a similar risk environment to normal operations ? and the M(M)EL words follow on from the answer to that question.
the MEL limitations discussed above do not apply since the aircraft is already in flight.
That's fine .. but it is a wise pilot who reviews the MEL after the situation has settled down .. the words provide a few more bits of the puzzle for his/her flight conduct decision processes.