ASW – Alternative hero leveling.

Besides, what does an elf need it for? Alpha troops are fast and have high attack. There's no time to waste on summoning.

Are you joking? If you played Heroes of Might and Magic, you wouldn't ask such questions.

Summoning is:
1) wasps (if they have decent, adequate knockback). Wasps control the enemy incredibly well while high-initiative elves finish them off. And wasps under a rain spell will give any chaos unit a run for its money.
2) mines - in terms of piercing power for ranged units, no comment needed
3) crystal, wall - to block approaches to ranged units, disable enemy ranged units, plus damage them with druid spikes
4) phantoms on blue ranged units
5) fan - again, a blocker that protects ranged units for free
6) raising the dead - to resurrect low-health ranged units if they are suddenly targeted by arrows or chaos units
7) enhanced fist with blue druids = high damage, piercing any defense

Summoning for elves is everything, with the right spellcasting. In the original game, it will mostly work the same way.

However, build your guild as you like. I don't care. I suggest we return to the topic of character upgrades.