A majority of them are contingency, established in =community_centre , churches, etc when needed Warming center - Wikipedia
Needs to be checked, but I doubt whether they are created as =social_facility in significant numbers now. In either case, they will need to be distinguished from other regular social_facility=shelter . While emergency:amenity=social_facility is unsuitable for =warm_bank , it might be worth reviewing for these, although I have some reservations about extending its use outside sudden disasters.