Transformations have 3 setting in total.
1. Full on cinematic transformation and camera angle
2. Just the transformation without the camera angle
3. KH2 drive style transformation where activating one makes you explode in burst of light and the weapon is instantly out
Transformations act as attacks that deal damage and push enemies so you get more bang for your buck damage wise by choosing to at least leave the transformation sequence on, no harm in taking off the camera though. It's speculated but not confirmed that the KH2 style mode of transforming does less damage since it's just a single burst but it's notably faster into a transformation this way.