Some of the metrics they judge are things that AMP basically implements for you, and are a pain to implement otherwise. Cumulative Layout Shift is one of those

Some of the metrics they judge are things that AMP basically implements for you, and are a pain to implement otherwise. Cumulative Layout Shift is one of those things. Content blocks on the page need to have a fixed height, not one that is dynamic (which might happen with lazy-loaded content). For some use cases, conditionally loading content (one of those being ads) becomes difficult/impossible if you're using a third party system and can't render server side.