According to Osho, the 'dry line' theory is needed as a provisional map for certain temperaments—the austere, cerebral, self-disciplined—who grow through dryness, detachment, and economy of energy. It protects them from dissipation and gives direction. Yet it is only a skillful means: useful until awareness flowers; then one must drop all theories and live from direct experience.
Some people need a plain, strict path that saves their energy; it helps for a while, then they can let it go.