Both of you can be correct: while some people, such as yourself, can see benefits, there can still be no research showing generalized positive effects, and some research showing generalized negative effects.
(Not saying GP is correct, as I'm not interested enough in the topic to know if their take on the research status is accurate. But your anecdote -- while great for you -- is not a basis for making generalizations.)
Just like with pretty much any other substance we use medically - it's good for some people but it comes with some side effects so if it's not doing anything for you it's probably best to abstain.
