As a therapist, this is not a technique I am trained in nor am i comfortable using. For me, I think it's important for a client to have control over what he or she reveals about him or herself in that person's own time.
I have, however, heard of it working and some therapists swear by it. In some cases, this helps with OCD symptoms and smoking cessation. I have also had client who rave about this and believe this is the way to go with things like getting rid of bad habits and revealing repressed memories.
There are no "rights" or "wrongs" when it comes to therapy methods as long as they are done ethically by trained professionals. It's more about what the client is comfortable with. Fortunately, therapists have specialties and there are many who specialize in this type of intervention and have conducted it quite successfully.
Long and short of it? Not for me (as the client or the therapist). But it can and has worked for many.