I can't go into details, but in general we closely track analytics for our product (like most companies with websites would) and run AB experiments to see how changes impact user behavior.
Also, given that the indicator for an AMP page is a greyscale, hard to see icon and words, people who don't want to use AMP might hit it because they are in a hurry and the text they are looking at is black and noticeable.
Which means even less reason to trust you.