Pls explain how early summoning spells are useful

[Blitz]

Behemoths are expensive, but very attainable in the early-game, and come just one level after raise skeletons at Enchantment 4. I like to mix behemoths in with my C'tis troops on my way up the enchantment tree. While early summons are rarely cost-effective when compared to their late-game counterparts, there are a few which stand out in the death tree. Outside of death, I rarely if ever use summons except the occasional seasonal while desperate and under siege.