KR Playoffs format

Why are the korean playoffs a single elimination bracket? What if the two best teams play against each other at the beginning?

LAN requires certain formats I think

They had a seeding determining round as well --> the seeding round determines who plays who and prevents the best two teams from playing each other immediately

yeah its a bad format, i believe the way it works is that the subdivisions of regions make the tournament format whichever way they want as long as they end up with the amount of teams they need to get for the lan event (in this case berlin). the heads of riot i believe tells each region how many teams they need for the event (na:3, emea:4, etc.) so the korean subdivision chose this format in order to get their two teams for berlin (the amount of teams korea were asked for from their region). obviously not the best format for the reason you listed above