Why don’t most tapeworms, roundworms, and annelids need ciliated cilia on the squamous epithelium?

Ciliated cilia are found in Flatworms. They serve for movement.
The tapeworms do not need to move. By absorbing nutrients from the surface of the body, the creature lives in the body of its “owner”.
Roundworms are more complex. They have muscles under the upper layer of the cuticle, which are called longitudinal. Therefore, these organisms can only bend. This gives them the ability to move in space ..
Ringworms have an even more complex principle. The structure of the skin is very simple – one layer of cells lines the surface of the cuticle, secreting mucus. And under it are the annular and longitudinal muscles. With the help of them, the creature moves in water or soil.
It turns out that the listed species have their own, more complex, opportunities for movement, or they do not need movement at all (tapeworms). That is why there are no ciliated cilia.