Personally, I had the collective view of reality beat into me (like everyone else) and psychedelics re-opened my thinking to the possibility of things like lucid dreaming, OBEs, etc. If not for psychedelics, I would have never gone on to learn, and continue learning, about religion, the human mind, philosophy, etc. They gave me a glimpse of the bigger picture. Some people need to be firmly booted out of normal reality a bit before accepting the possibilities. A near death experience could do the same sort of thing for a person, but those are harder to come by.

Most other drugs dull your senses and narrow your view. Not a horrible path for small detours, but a dead end if you stay on it, in my experience. When I drank/smoked daily, dream recall went to zero, and interest in philosophy/paranormal waned. Psychedelics, for me, are a learning aid. I don't use them the way I used to use drugs.

Actually, in most of the scientific type reading I've done, psychedelics aren't even classified as drugs.