If I can choose to watch ads between my streamer's matches, I'd watch way more add than I do currently (add captcha to avoid bots) and not miss any of the action.
Also, if I watch more than X ads per hour, I get to watch them without audio and with streamer audio, so I still have a small streamer window with its audio. Twitch'd make more money and viewers wouldn't be angry whenever something worth watching is happening and the ads ruin their experience.