If it turned out to work great in practice and people started using it en masse, the benefits would greatly outweigh the costs IMO, particularly if it snuffed out Covid and/or the flu. If it ends up being a niche thing, I doubt it would bite into the resistance numbers.

Besides, we're already spiraling down the resistance chasm with antibacterial soaps, stuffing cattle with antibiotics, overprescribing, and so on.