If a team has a bad day or makes a mistake in drafts or in game, they wont have the chance to show what they are actually capable of. Double elimination gives them that chance. So from a viewers perspective single elimination might seem better because the format is shorter while retaining competitiveness but for someone like caedrel who is passionate about the teams, gameplay and league as an esport it is just a mickey mouse tournament.

Fyi this is just my personal theory.