Do you know how to play?

Handling Chain Lightning in special buildings requires a certain level of skill.

That's exactly it! The effectiveness of using it in battle depends on how the enemy stacks are positioned and how many there are. "One clumsy move" :) - and you'll "fry" your own troops. :( Not to mention that on the second turn, when you engage in melee combat, you won't be able to use the lightning anymore. :( One, but very powerful strike - it depends on the magic power and the total health of the enemy. Therefore, lightning is more often useful against a not very large group of neutral creatures or when storming a castle without a hero defender.