No need to apologize. I am just pointing out the disorganized thought process and self-contradiction to help refine your thinking and theory to something that "makes more sense" if that makes sense (in other news, redundancy is redundant). You are thinking and formulating possibilities, which is a positive trait.
I agree with this to an extent. I wouldn't say it's completely useless. Elluka notes that the sword's magic was "weak" when the Demon was absent so there was something there, just nothing signifigant compared to when the demon was present. Whether or not that is enough magic for her plans, I can't say.
The crux here is that we don't know what Ma is planning. It's all but confirmed she has her own agenda, but she isn't sharing the details, just letting everyone else do the work for her. The issue you have with her "not being bothered" by the Sword and (in my opinion) the Scissors being devoid of a demon is because you are thinking with the mentality that she needs them to awaken in order to fulfill her plan. We can't make that assumption.
When the wiki polled a while back what we thought would happen when all the Deadly Sins were assembled, I firmly stood in the "nothing" corner. Ma is the only one to have mentioned this wish that can turn Hell into a utopia if you collect the sins, which only adds to my wariness with her reaction to Gammon's dream. I feel neither Hell nor utopia will result from their gathering, they will just be seven magical objects brought back together.