Both of mine have been a lot of own therapy, yes. One was okay for me, the other one (~75 yo, with apparently 40+ years of own therapy) pretty horrible and constantly caught up in his issues and infusing my therapy with them. I would have never assumed that some Ts never had therapy themselves until I read about such cases. It sounds weird, maybe like a mechanic who never took apart a car or other machines but offers to fix them for others. I definitely had a different idea of what it might be like to be in therapy before trying it myself for a while in spite of studying lots of psychology.

So I do think that the first hand experience should bring them closer to the reality of it, but I do not believe that alone would make them more competent, compassionate, helpful, or objective. I would think it is part of their training and professional experience but far from enough to make someone effective.

Actually, I found the most helpful person for my main issue in a peer support group. He also had a background as a therapist, but that's not how I met him. I liked those groups because people really understood each-other and could also offer practical advice that actually was realistic and effective, all based on first hand experience. A T that was never a client in therapy sounds rather bizarre to me, but simply "working on their own issues" is hardly enough I think, if for nothing else, because people have all kinds of issues. My bad T had all that experience but a main problem area between us was that we were radically different in personality, backgrounds, problems etc and he seemed to be only able to work effectively within a narrow area that he was familiar with.