It's not the Auction, the game had lots of players standing around in cities who weren't using it. People used to socialise as well as playing but now a lot of them are on that Line nowadays.
It's got to the stage where people don't come online in-game until someone sends a message to them via Line, informing them when something interesting is happening.
I don't use it but I know a lot of guilds do have a Line thingy where they all disappear to.
It's ok for those who suffer from fomo too.