AMP pages load faster. They make the user in a satisfied state of mind. Compare this to pages that are slow to load, consume all the device’s battery and resources. Today the ads on slow loading pages yield more revenue to publishers (RPM) from header bidding capabilities not present yet in AMP HTML ad formats. At some point tech will catch up. As a brand it is more profitable and effective to advertise to a user in good mood because the page loads instantly. AMP ads, like pages, deliver the premium user experience. Canonical pages running standard HTML will eventually have to get faster, perhaps running AMP as well, as time goes.
AMP 0.1 dilemma: high performance, missing ad monetization features
As of January 2017 the performance aspects of AMP pages are largely achieved, when considering load times. However, the ad ecosystem has not moved to AMP yet, resulting in limited inventory for AMP ad units. Also, features that increase the value of ads for publishers are also missing, like header bidding. This means that for now, while the user experience is great and that over time AMP ads should yield the best overall return on investment, today they yield less. If you are running an ad-funded site and turn on AMP pages, be aware that your RPMs and CPMs are going to drop, temporarily. If your users benefit greatly from increased speeds you may compensate this loss by serving more pages. But it’s not a given as of today. The higher value of AMP ads for now is in serving ads within the framework of a positive user experience. For dollars, it will take longer.