Distinguish a discipline's primary technical aim from its broader benefits. Maʿani aims at avoiding error in conveying an intended meaning appropriately; improved understanding can be one consequence.
Bayan studies ways and degrees of expressing meaning; effective imagery may be one benefit. Badiʿ recognizes appropriate beauties of expression, but does not replace the other disciplines.
A useful effect should not automatically be mistaken for the discipline's defining object or primary purpose.