So, instead of actually using AMP, you could just follow the AMP guidelines and get most of the speed benefits with almost no downsides. But Google started prioritizing AMP pages in search results, so now there's a downside either way.
You can beat AMP's performance with hand-tuned optimizations. Its goal is to uplift performance across a significant percentage of web content (instead of just that developed by the few experts).
Is Google going to penalize my sites if we don't use it? No, AMP is not a ranking factor.
We don't include advertising in our pages, so should we care about AMP? Advertising is to AMP like Advertising is to the Web. E-commerce is a big use case where advertising is uncommon.
I understand that AMP is not a ranking factor (except for its inherent speed, perhaps). However, is there not a carousal at the top of SERPs for pages in your AMP Cache?
So while not an organic ranking factor, it would still affect SEO. Is that a fair comment? Or am I missing another perspective?
As far as I see it, Google sees this as valuable to their interests, and have made clear what the talking points are and what should and should not be responded to. That's the only reason I can think of for this counter argument to be continually ignored by him.