It is very interesting point of view. I think in some point it might work, although I assume not in every situation it will be reasonable to use it. There is a very slight border between bravery and stupidity and while "fake it till you make it" may help in encouraging us to do something in a good way, in another situations it can cause some troubles.
If we want to start the new hobby or learn the new language but we have low self-esteem, it might help.
If we are afraid to juggle with the machetes, fake it till you make it wont help and most possibly we will end in the hospital :))
Thanks @papi.mati I totally agree with you on the machetes or anything that requires you being a bit of a dare devil.
Most of my clients get benefit from just taking on a Power Pose before doing something they are nervous about. Movement and posture alone can give you confidence.
What technique do you use to push through your comfort zone?