It's not only not faster but it's often slower — AMP puts 100KB of render-blocking JavaScript into the critical path. If you can render a page with less than that, you're likely to beat it, which I see regularly on iOS.
Not only that, but because of the limitations of AMP, many AMP sites are getting slower and slower as they attempt workarounds. I've seen many sites recently that do section headers as a large image-as-text, I'd guess because they want to use a custom font? Even worse is AMP won't load images until you've scrolled them into view.