If the necessity payments are biweekly or whatever, and actually scaled to necessities, and spending of them is actually limited to necessities, it shouldn't be possible to save many of them up, and not very beneficial either. So there isn't a huge benefit to making them survive bankruptcy (the court could even award an extra necessity payment right after adjudicating the bankruptcy).

So I think that is a good argument against them being, uh, necessary, and then there is the whole thing where if it is a real currency, it will be fungible, so people will still be able to use them stupidly on things that aren't necessities.