Trucido, “neutron bombs” are real–the proper term is the one Derleth supplied. As a result of some botched explanations early on, the general public has a very distorted idea of what the bombs are made to do and how they work. The bombs are real, but the “kills people and leaves buildings standing” conception of them is a myth. “Kills people, wrecks everything nearby, and leaves a large area uninhabitable for a long time” is a shade nearer the mark.
Derleth can probably correct me if I’m mistaken, but I believe that in addition to rendering some materials horrendously radioactive and producing really nasty fallout, ER bombs cause marked physical deterioration in some structural substances like cement. Even outside the blast radius, the radiation can render cement walls brittle and prone to crumbling. So yes, it destroys buildings–and in more mays than one. The “advantage” of such bombs is that it’s more difficult for one’s enemies to contrive shielding that will keep the radiation from making them come apart like wet tissue paper.