OFB-12

when they play BO3 and the winner advances to the final bracket, while the loser doesn't, there's no point in agreeing to a draw. The host will then flip a coin and determine the winner.

You are simply confirming my statement: BO3 with advancement to the final bracket is a single-elimination game, not a Swiss system or other round-robin competition system. Naturally, there's no point in agreeing to a draw in single-elimination games.