Because of all the Europeans.
Lost Ark is big. How big? Breaking over one million concurrent users on Steam big. And because of how many are playing, access has been spotty with queues on numerous servers. Noting how many Europeans are attempting to access the game, Lost Ark today announced a second region for European players.
Due to overwhelming demand in Europe 2 we are opening a second region for players: Europe West. This has been a complex process that required 24/7 effort from both the Amazon Games and Smilegate RPG teams. We want to thank you for your patience while we worked on this. We’ve been blown away by the number of players and can’t wait to welcome more of you into Arkesia.
To compensate players for moving servers, the launch gift will be given to everyone. Also the last ten days of login rewards will be granted to all players on the new Europe West servers as well as a bonus set of login rewards for the next ten days. All players who bought a founder’s pack will be able to acquire an extra set of those items starting February 19.
Amazon and Smilegate expect the Europe West server cluster to lower, but not eliminate, login queues.
Source: Lost Ark