Why should I not apply anamorphosis correction to all images ?

This information applies to version(s): 3, 4

Correcting anamorphosis introduces some level of distortion in order to restore proportions, and therefore does not always maintain rectilinear shapes.

This means that you, based on what's in your photo, should make a trade-off decision between maintaining straight lines and restoring the natural proportions of the objects in the photo.