I think there might be an equivocation on "experience" in the case of those altered states. If you must drastically change the brain to encounter nothingness, such as by falling asleep or taking drugs, this isn't really an experience, assuming we're talking about the normal kind of perceptions by the awake, healthy mind.

But certainly, eerie quasi-experiences have impacted religion, philosophy, and art, forcing the explorers to assimilate the bizarre into their worldviews.