Almost any drug can be used for introspection to some extent, but I would say that deliriants probably aren't your best bet for that, in my opinion there's other areas where they excel, but I won't go too much into that in this topic. (suffice to say they're excellent tools for dreaming for one!)
In terms of introspection though they can often leave the person taking them feeling completely sober mentally, even when vastly confused and not even realising they took a drug etc, from my limited experience with deliriants they never really altered my thinking patterns out of the norm, aside from convincing me that some of my lifelike hallucinations were real, and as such they would be no more useful for introspection than simply being sober.
They are often quite relaxing though and this could allow for an easier transition into an introspective state in someone with physical ailments preventing them from relaxing and clearing their mind fully etc.
Also, to the above reply, Ketamine is a dissociative not a deliriant, vaaaaastly different classes of drugs. I too have found Ketamine to be incredibly introspective, but deliriants? Not so much.
I think if you're going to use deliriants as teachers you'd be better off using the lucid dream states they can provide in the wake of the day of your experience.