Catering to some of the more hardcore players of Grand Prix, the Battle Bar is a training ground for those who want to excel in Duel, Hunting Ground and Raids; many of the more senior clans often do IRL meets here in advance of Raids in order to prepare their teams for the event.
It's rumored that a few of the Grand Prix game devs have created secret test stages that can only be accessed offline at the Battle Bar, but no one has been able to confirm.