IMGHaste Service Worker acts as a middle-man between your visitors and your webserver. It is part of the White Label solution that we offer, to be 100% undetectable from bot traffic.
This way, your users will get all benefits, while you won’t suffer any sudden overcharges if a bot decides to crawl your website and get all your image content.
You only pay for user experience improvement.
Finally, to share a secret here, Google indeed checks your speed performance but not directly the lighthouse tool, it gathers user data from GA metrics as well as collecting data from Google Chrome sampling (~2‰)