"Did you find any practical purpose to the "altered" states of consciousness?"

Yes. I found them very useful for understanding myself. They confronted me with many unpleasant (and pleasant) but important parts of my life and feelings that I was in denial of or just couldn't experience in ordinary consciousness. They helped me gain a lot of insight in to myself and in to the world.

Another benefit was shaking my certainties about what the world was really like. Up to my first psychedelic experience, I felt pretty comfortable in the world (not that I had a pleasant childhood or life or anything, but I did feel I knew what the world was like, and how to get around in it). Psychedelics radically changed that. Even though I'd read a lot about them before I tried them, and was intellectually prepared for what I experienced, actually experiencing it was a different matter entirely. It's like reading about sex vs actually having sex. Reading about being in love vs actually being in love. There's no comparison.

Likewise, on psychedelics, suddenly I was not in Kansas anymore (metaphorically speaking). I learned that reality could be very different from what I take it to be in ordinary consciousness. And, while in an altered state of consciousness, what I experience could feel "even more real than real". This made me interested in finding out what reality was really like (if that's possible), and led me to become interested in and study philosophy, psychology, and religion.

My psychedelic experiences made me much more laid back, less dogmatic, and more accepting of other people and other views of the world. It also helped a lot with empathy. During a psychedelic experience, I became much more sensitive to my own body, my own feelings, the feelings of people around me, even the feelings of animals and even inanimate objects, which could become animate or even a part of me. I experienced the feeling of being one with everything.

After coming back to ordinary consciousness, those feelings subsided or disappeared entirely. Objects certainly became inanimate again. Still, the thought of the possibility that they were actually animate, and especially the possibility that things like trees might have feelings -- or at the least that I should respect them more than I do, or that they may "know" or "understand" more than I usually give them credit for, or be able to act in ways that I'm not normally aware of remained. And I think I am generally more sensitive towards the feelings of other people now, especially if they are in some sort of distress.

I came to be open to the possibility that there is a god or gods, or at least some sort of sacred reality beyond the one I had access to in ordinary consciousness. I did have experiences where I communicated with various entities and gods. Whether this was real or imaginary I can't say. But I am now more open to the possibility that something like that could be real, and I am more understanding of those people who have had profound mystical experiences or experiences of meeting or talking to God/gods.

Now, I can't give exclusive credit to psychedelics to changing my views on all of these things. Transitioning to my present views on these subjects took a long time, and my psychedelic experiences took place a very long time ago. But they opened the door and showed me the way on many of these things. How "practical" these insights and attitudinal changes have been would depend on what you mean by "practical". They certainly have been profound and important to me. But I can't say I came up with a new invention (as some people have) on psychedelics. Nor did I solve a math problem using them. They didn't make me a better coder. But they were very valuable.

Some studies have actually been done on using psychedelics to enhance creativity. If you are interested, I recommend reading James Fadiman's "The Psychedelic Explorer's Guide", and Oscar Janiger's "LSD, Spirituality, and the Creative Process".

On a humbler note, meditation has helped me to achieve calm (at least while I'm meditating and for some hours afterwards). I view that as a very practical effect.

"I would also like to suggest substituting the word "altered" with "disturbed". Would you mind telling me your thoughts on this (whether in connection with the above question, or not)?"

I don't like using the word "disturbed" for these states. Certainly, sometimes when in these states one can be confronted with visions or feelings that one finds disturbing. Aldous Huxley titled a book of his about psychedelics "Heaven and Hell", and that is sometimes quite an appropriate description of some of the more extreme experiences that one can have on psychedelics or in other non-ordinary states of consciousness. However, they are not always hellish, nor always heavenly. They can be quite unpredictable (especially when used in a haphazard, uninformed, or destructive way). I would agree that those states are non-ordinary -- in that they differ from the ordinary state of consciousness most of us inhabit during our waking lives. But to paint them all indiscriminately with the pejorative term "disturbed" is to misunderstand their nature.

It's also a bit arrogant to put ordinary consciousness up on a pedestal as if it was the ultimate and best form of consciousness and the rest were lacking, wrong, or immoral in some way. Many Buddhists and Hindus would certainly disagree with anyone who tried to claim that the enlightened state of consciousness was "disturbed". From their perspective, it is the ordinary state of consciousness which is "disturbed", and the enlightened state of consciousness that is healthy. Who are we to insist otherwise?