It could be said that it was a countermeasure that took advantage of the dungeon's characteristics. If this is a water prison, you can't prevent it with this method. Because I always have to carry and install a lightning rod.
Ah, but... water conducts electricity easily, so it gets absorbed by wet walls and the like, so I wonder if its strength will weaken? In addition, water-based magic attacks were enough to torment adventurers.
So, in most cases, the boss only had the wind spirit ball, and the water spirit ball was probably buried somewhere in the boss stage. In the wind dungeon, if you take down the boss, you can't pick up the spirit ball unless you leave the dungeon, so you can't even check if there is a spirit orb. That's why it's hard to convey thunder magic.