I'd argue that, for the metrics, it's vastly MORE important that viewers turn this off. There's more viewers than streamers, so even if every streamer turned this off, if viewers don't, the executives can still claim that "most users don't care" and cram it down our throats even harder. Opt out.
Even if you're just a viewer and not a streamer, tell them through metrics that you reject AI: Twitch.tv > Settings > Security and Privacy > Training for Generative AI: OFF