Why warships still favour shaft-and-screw propulsion

Why do warships usually use shaft-and-screw propulsion instead of pod drives?

Most pod systems are unsuitable for high speed, while high-speed alternatives are expensive, so conventional shafts remain the cheaper practical option.

Pod systems are less common on warships principally because conventional versions are not designed for the required speed. The alternatives capable of higher speed are costly, so shaft-and-screw arrangements remain the practical choice for budget-constrained navies. Propulsion choice is therefore an economic compromise as well as a hydrodynamic one. A future Type 83-era design could alter that balance.