As suggested in the answer of GM Fralucar to my my support ticket, i will share my thoughts in this forum aswell.
This week i bought the event cashshop items so i could get the Devil Tail box. I was happy to see this item finally being sold, since only the EU version of the game never received it.
Unfortunately it surprised me to see the box is missing the black version of the Devil Tail. The box describes itself to allow free choice between the colors. The black version exists on the NA server so i had naturally assumed we would finally get it aswell.
The release of the long missing Devil Tail box was an attempt to synchronize the EU and NA versions of the game, which are almost completely handled equally. This step is appreciated, since it goes in the direction many players want. Although not giving EU the same options as NA for no apparent reason comes as a big surprise, since it keeps the disparity and possibly angers half of the playerbase (EU server in this case).
Here is a small overview of current differences (known to me) between EU and NA: Black Devil Tail - Available on NA, missing on EU aswell as missing in current resale for NA
Rockstar Outfits - Available on NA, missing on EU
Oriental Armor - Available on EU, missing on NA
Likewise there are alot of highly requested cosmetics still missing from the EU and NA versions of the game that we never got the chance to access. Alot of other regions do however, which is frustrating to alot of players.
This is better described in Furiel's forum post
I would love if this could reach the developers so they can improve in their way of future updates regarding version exclusives and especially in resolving version differences between EU and NA.