These are probably my favourite mini-bosses in the game for a bunch of reasons:
A) They actually need preparation. You can't just waltz in without confetti and pacifying agent. So unless you're in for a hell of a lot of pain, use these.
B) The slowing effect means you actually have to think when dodging and deflecting. Only the case of the terrestrial ones, but still a cool mechanic.
C)Horrifying as all hell. We all saw some disturbing **** in From games, but these... these are special, especially given the lore behind them. Really serves as a reminder of how ****ed up demons and ghosts were in Japanese mythology, even if these are just inspired by them.
D) Yashariku is my favorite, since the "illusion" one that's close to it is actually his twin brother that supposedly was never born. Ties great to the whole "halves your hp" mechanic that the sugar and spiritfall has.
Now, I honestly don't understand what some people complain about. This is a From game, you cannot expect to R1 spam every single mob and then just brag you won the game. There are multiple tools that affect apparitions, the whistle and the upgraded shield comming to mind first. You have all the tools you need to beat these pretty early (confetti, agent), and you get even more tools to make them trivial later. You can even farm the confetti from the samurai in the castle. Plus, the rewards are actualy relevant, since you can sell the candy and make money while using the spiritfall.
TL;DR: Git gud, stop complaining.