Advertisers that care a lot about engagement use CTR instead of CPM. CTR enables advertisers to keep track of engagement and lie about real engagement numbers to save costs. If advertisers rely on video segment statistics, creators can fake the statistics to earn more money. So advertisers rarely measure their payout based on unverifiable information. And people that use SponsorBlock wouldn’t buy it, even without SponsorBlock. Or in other words: Most creators can ignore SponsorBlock.