I bet someone could read the messages in these videos quite easily under the influence of cannabis, but I doubt most would be comfortable at that level of intoxication to enjoy the experience while it occurred.
ime/imo the main reason why it's so uncommon is because you have to go _comically_ far over your tolerance to hit the truly-psychedelic effects, and, as you said, it can be deeply uncomfortable. I've only ever managed to hit truly-psychedelic effects by ex. eating 600mg of RSO with a low tolerance, or doing a dab after a t break and way overestimating my tolerance.
I tried taking something like 50mg THC once and it just made me feel like my head was imploding for around five hours. No visuals or altered thoughts or anything. Made me conclude that my brain probably just isn't receptive to weed or something.