AMP allows tech people at non-tech companies to push back against all the "just one tiny little thing it won't effect load speed much" requests.

Your marketing department wants another tracking script? no can do. Your exec wants a javascript "click the monkey" promo? not on the AMP site. The UX folks want parallax webGL spinning logos? Sorry AMP doesn't allow it.

It puts people who were previously not in a position where they could push back against decisions which effect load speed in a position where they can push back.