This is my thought as well.

As I've shared here previously, my therapist had also crossed boundaries with me and the relationship went outside of the office eventually, though it didn't become sexual.

Without going into details I can say that I also felt on top of the world because at that time I felt like that guy was helping me like no one else had ever helped me before. I never felt accepted for who I was, which made me feel like something was innately wrong with me. That therapist made me feel special and may be he was right to some extend. There are some things about me that are special and a few people in my life noticed that and told me about it. He was one of them and he did it best. His feedback was not just flattering, it was insightful. It made me more aware of my natural gifts and convinced me that I needed to put those abilities into a good use, I needed to do something with them. This was objectively helpful. What was not helpful though is that he put me on the pedestal and treated me like a God (he literally said once that he was seeing God in me) instead of helping me find practical ways of using my gifts for my and other people's benefit. But at the time his admiration felt like nirvana and it felt like that was exactly the kind of help I needed. In reality, as I realized in hindsight, he just inflated my ego and left me with no ideas, no practical skills and no ability to find practical applications for my natural gifts. His professional responsibility to me, as I see it, was to help me understand what prevented me from becoming what I always wanted to be - self-sufficient, creative and productive. He never did that. He pointed out my potential, but he never helped me understand how to use it and how to manifest it in the real world full of external obstacles.

So, yeah, back to your point, what feels helpful in the moment, may turn into a mess in the future. And, when intense emotions are involved, it is difficult to make an accurate assessment of whether something is helpful or if it just feels good.