In general I have found that for someone not well versed in a Shamanic tradition and experienced with alternate states of mind brought on without intoxicants will not gain anything using them in their practice. In the cultures that use peyote and other hallucinogens, even mild ones like pot, restrict them only to well trained shamans. There are good and valid reasons for this. We should respect those cultures and their reasoning. They have had thousands of years of experience with this stuff.
Keep a clear head and things will appear much clearer to you.
Let me make another
amendment. I agree with you. If a mind-altering plant like Peyote is used in a mindful fashion, and not constantly, it can be a wonderful thing. I think that true shamans learned to use it as a stepping stone to higher mind sates, and once these states could be achieved without the drug, they abandoned them. This is not how it is in every culture; but I think that the spiritual stepping stone must be abandoned sometime. It is not in my power to dictate what kind of stepping stone is used. I would just rather not use a drug from the start, but hey, it could even be helpful. However, abuse of a drug for entertainment, like you mentioned, is a terrible thing.