The Search team will try to weasel out of this claim, but AMP results do get prefrential treatment. It’s almost impossible for something to rank above the Top Stories carousel, unless you’re searching for something like “facebook”, which, yeah, the top result is going to be facebook.com.
This is the aspect of AMP I’m by far least comfortable with, but Google gonna Google. They’ve been dangling carrots in front of publishers for twenty-one years. And the now-ubiquitous ⚡️ has pretty good user recognition. It’s a pledge: “This site is fast; in fact, it’s instant. This site won’t jump around under your thumb. This site doesn’t have obtrusive ads. This site won’t try any shenanigans like redirecting you to the App Store page for Clash of Clans”.
You can’t make those promises with 100% bulletproof statically verifiable certainty without AMP.