It's obvious to some of us, but apparently the developer(s) doesn't care.
I don't care if there are new "toys". It is my choice to buy them or not, but...
If a level 100 player purchases the wrath cloak, the huge damage increase allows them to farm bosses for unlimited items (stones, courage masks, etc). This becomes a loop as the player mines objects that increase strength, energy regen, extra-damage, which allows them to kill bosses faster.
"Older" players can never catch up.
I complained before about the fact that low level players were able to do outrageous damage by purchasing items. I was pretty much ignored. I expect to be ignored again.
I have to assume that there is exactly one reason for the introduction of these items in this way; Money. "Limited time" generally means that someone will shell out real cash to get the RCs to buy it, rather that getting them through playing.