I think there's two skills here: the skill of choosing beliefs and the skill of internalizing them.

The usefulness of choosing beliefs stems from several applications: 1. Choosing to believe things in order to intentionally set cognitive biases. (eg. believing every moment meets some needs of mine combines with an understanding of fundamental human needs to prime my brain to spot how my needs are being met in the moment...particularly helpful for painful moments, which can meet my need to learn how to better meet my needs) 2. Choosing to believe the opposite of problematic thoughts. (discovered this one by choosing to stop believing an anxious thought that was plaguing me) 3. Choosing to believe I can safely abandon my judgments. (which accidentally changed my food, music, media, and people preferences to be WAY more inclusive) 4. Choosing to believe I can learn to identify as a woman in the future. (accidentally creating a second conscious voice in my head, ie. stumbling on the Buddhist practice of deity visualization)

Internalizing a belief is when the thought processes change based on the belief. Some beliefs are easier to internalize than others. I've got no idea what goes into determining the time required & am also uncertain if it truly is a skill we can learn.

I've heard such internalized beliefs described as "aliefs", indicating that they are, in a way, more fundamental. As an example, if you're walking in a dark forest at night, you might rationally believe that noone is hiding there waiting to murder you, but if you don't alieve that the forest is safe, that doesn't stop you from feeling unsettled.