Helpful or not helpful also depends on what you bring to the conversation and who you are talking with. There are some sick and some inept therapists out there. Be careful.
Generally, it works, or people would not do it. Taking a break from therapy once in a while is not that bad for some of us to do either. Although, overall, therapy is helpful, there "is a season" for everything. Once significant progress has been made, there is a period of leveling off, a plateau. When a plateau is reached, I believe, it's time to do some other work on the new level and with the new perspectives that have been reached. Okay, you've trained to a point, now what can you do with it? If this realization is not had, then the opportunity to really LIVE and not just talk about life, is lost. There just comes a point when we have to try something new, break out of routines, and get creative and industrious.
So my answer is, Yes, therapy is not only a good idea for people with diagnoses like PTSD, but it would benefit almost anyone, because we could all use a boost and new people are "fully conscious."
Therapy, and mental health, is defined by some as transferring the "unconscious" to the "conscious" realm. Thus, becoming more aware of self and others. None can introspect 100%, so therapy can help increase whatever percentage we are functioning at.
My personal philosophy is that The Teacher Is Always Present, or that the higher self is never totally absent, or that "god" is never totally absent. Thus, we can and should feel lead to draw a line now and then, and say, "I'm taking a break from X and going to try this new project in life with what I just learned."
This takes bravery and vision and confidence, which was developed, hopefully, during therapeutic times and is now able to be applied. But the awareness that therapy may need to be used if stuck in a rut later is not a negative; it's an awareness of the cyclic nature of life. As a toddler likes to have adventures but needs to "check in" with a safe adult now and then, so do we need to have a sanctuary. It can be counseling, therapy, or a spiritual outlet or a special relationship or place, even in our mind.
Heidi, it's possible you are angry at therapy and it's also possible this is not a season of therapeutic growth. It may be a time for action and for doing other things. All roads lead to Rome, as it were, and all efforts will ultimately lead us back to ourselves on a deeper level whether we like that or not.