Nominal I have no idea why spots announcers weren't dumped decades ago. They're a holdover from the bygone era when radio was the primary means everyone had to experience a game. Any regular fan knows enough to not need their commentary, which is useless at best and actively detracts from the experience at worst.
E-sports desperately needs to drop the announcers. They're just as terrible with an extra dose of your typical shouting Let's Player. Even as someone who must have sunk 3000 hours of their miserable life into DotA games and Starcraft, I can't stand watching broadcast games because of the announcers.