Actually, it is not true that every land should have a landuse attached. I've often heard that as guidance for new mappers. Most land is not used. Look around European countries that have much more thorough landuse mapping--they never map at single building-level granularity. But in the case of this specific place of worship, I would definitely map the broader area as landuse=residential. If you are standing in the lawn of that Kingdom Hall of J.W., would you feel like you are standing in a residential neighborhood, or would you feel like you are on religiously significant land? I would definitely say I'm standing in a residential neighborhood, and the Hall is inside the neighborhood 