In short: Farming 2.0. A bunch of NPC’s patrolling/running around, with the event active circle, killing a horde of monsters that appears In the appropriate time. XP Is rewarded based on the time all the mobs have been wiped. It also gets increased altogether with the mob level/difficulty, that If everyone gets wiped, the event resets but It goes on and on In a loop.
To give an “interesting” option to grind/farm and to let the world more “alive”.