I dont think this is a Cover event, it's more like some weeb from CGV holding it, and they were granted permission after asking. If it's a Cover event they would have announced it on their own twitter.
The point is the atmosphere. Basically paying to watch the live with an audience and get hyped with them.
Same reason you go to movie, a ticket cost way more than piratesbay and you gamble dice roll of having a crying baby next to you or a girl not understand what the fuck is happening and her boyfriend spoil the whole movie every 2 seconds trying to explain it to her and paid money for overpriced corn.
Even for movie there isnt a reason to go to a cinema if you just only look at the price
At least going to weeb event like this you wont get to roll the dice.