"Magic is about visualization"
Isn't it interesting that Macht's signature spell isn't "violent" in the traditional sense. It's described as a curse: Changing the property of anything into indestructible gold. But by itself that's all it does.
Can we assume Macht didn't (could not) visualize himself ending Weise using pure violence? Encasing the entire city in gold wasn't his only option. He could've rained down gold flakes and have everyone bleed out in the streets but instead he decided to immortalize the city and the surrounding region.
It's preservation, in a way.
What a tender ending he chose. As a demon who is born with instincts of hunting and devouring humans, for him to default to his magic, for his magic to be something that doesn't destroy but perserve as indestructible gold, is so very tragic.
In some ways it reminds me of Wirbel, who needs time before he can make the killing blow. Macht too, is delaying the inevitable, except his procrastination lasts as long as his magic holds. Which until Frieren came along, could be as long as forever.
