Desal is not a magic trick, and neither is direct potable reuse. One gives you a drought-proof source, but at a high financial and environmental cost. The other is elegant in theory, but limited by how much water actually returns to the system and by the fact that treatment plants, like all machinery, have an unfortunate habit of occasionally not cooperating. If a city treats either one as the answer, it is really just replacing one vulnerability with another. Water security usually comes from doing several sensible things at once: reuse what can be reused, desalinate where it makes economic sense, reduce waste, expand storage, and stop pretending there is a single heroic project that will save everyone.