Pls explain how early summoning spells are useful

[Aleph]

Just to be clear - I wasn't advocating the Eater, just saying what he's for.

I think my favorite overkill late game use for astral gems (besides wishing for SC chasses and blood slaves) is something I saw in the Alexander's Tome. Golem + 3 astral boost items + Cloak of Shadows + Luck shield/faithful + Ritual of Return, tucked in a corner of the battlefield, scripted with Astral Tempest, Doom, and Astral Geyserx3 and loaded with 10 pearls, and teleported at a large enemy stack. Get 2 golems, switch the gear back and forth between them, one casts teleport every round while the other casts ritual of return. It's fairly effective at whittling away large armies of regular troops and slapping afflictions/horror marks/curses on tougher ones, and also has the silly fun aspect which eater of the dead has without the inevitable loss.