Plus putting it out in the open can help some clients realize it is not them but therapy or the therapist that is the problem. Too many can easily buy into the if it isn't working it is because
a. Client is not doing the work (total ******** to me)
b. It must get worse before it gets better (with no timeline or idea of what is good worse versus bad worse)
c. Complete submission to the therapist's master plan and all will be well eventually and ps. client you don't get to know what that master plan is - just trust the stranger. It is not working because you don't trust the stranger enough.

So I think it very useful indeed to help people put their experiences into perspective and to learn that a therapist is not a god, does not have answers, therapy is not the only answer to a problem, and if it is not helping - it really could be the therapist or therapy and not the fault of the client (despite what therapists and other people tell you)