I'm not sure what you mean by "can not be measured" because everything you then go on to mention is clearly measurable to some extent
I want to say I agree with a lot of what you're saying here because it is true that hallucinations can drastically change people's lives. So long as people are intellectually honest about this then there is no problem (too many people judge the extent to which something changed their life to be equal to the extent of its content's validity i.e. "my vision of Jesus was so profound and changed my life completely, that's why I think Jesus is real"). What I disagree with is the definitions used here. Dreams are real experiences, as are any hallucination. They can be measured, analysed, discussed etc. The distinction is that they are not experiences of the real.