They don't give any of this, since they are literally Summons from the pillars.
I believe their bodies can be blessed tho, and give you a demon dust.
On a side note: every summon is like that: no experience, no loot, no bestiary. The bodies of summons tend to just "puff" when they die, just like when you kill a ghost summoned by a necromancer, they don't leave a body on the floor. For some unknown reason, the demons summoned by the pillar become dead demons, and do not "puff", therefor their bodies should be "blessed-able" (I invented this word, I think).