I disagree. There are times when miracling a Kaiser is the smartest move you can make.
For example, suppose you already have a solid fire team: Mars, Ama, Uriel, Svarog, Dakki, and 1 other good hime (Amon, Acala orAries). You are way better off miracling a Kaiser than another fire hime for several reasons.
1) Fire tower is done, and that extra hime isn't going to help you much.
2) The odds of pulling a hime from a random gatcha pull are a lot higher than the odds of pulling a Kaiser. I must have pulled over 100 SSR hime, including dupes, but have only pulled 5 kaisers. in fact, i have pulled more PTW's than Kaisers. This is because I whale hard on PTW boosted gathca. At least such a thing exisits. Kaisers are never ever boosted. If they were, I would whale hard for them too.
3) Imagine you miracle a hime anyway, and then pull a dupe the very next week. If they have a really OP wep, you might be like "Cool, now I only need 2 bricks instead of 3," but most likely you're going to scream FML so loud you wake up your neighbor's baby. Pulling a Kaiser dupe isn't a problem at all.
As for the forthcoming Eid brick event, well, if you don't have a single PTW yet, then you can use that to break your Kaiser, but if you do, you'll most likely want to brick your PTW instead, so it still makes sense to miracle a Kaiser.