Spamming advertising in chat is a bannable offense. Chat is a space free of ads, because there is no way to opt out without closing chat, and if I do that, I have literally no reason to watch the streamer on Twitch, since I can probably catch their VOD on YouTube the next day. If I want to watch the streamer on Twitch ad free, I subscribe, which kicks 50% or 30% over to Twitch to pay to keep the lights on. The comments by this bot announcing this campaign probably got it flagged to Twitch by thousands of viewers and banned in thousands of channels, because it's the same behavior seen by other bots trying to entice you with "free gaming gear" or "hot singles in your area".
The AI scanning as part of this campaign is happening whether someone opts in or not. And what the streamer opts into is nothing more than being used as an advertising vessel for bad sugar water for free.
Pepsico is free to issue Twitch bounties for certain things or buy normal ad slots for pre-rolls or mid-stream ads if they want to remind everyone that their neon green slop exists.