Over the last couple years Google has acted like a dictator on the web. No more autoplay... except if you're Youtube, or these 100 approved sites. If you use Chrome... oh now you're auto signed in. You opt out of location tracking - we'll still track you, we don't care.

Don't give Google more power.

Implementing your website in AMP is basically handing the keys of the web over to Google. They're going to make it more and more ridiculous to stay AMP-compliant and you're going to be shut out if you don't play their game. Eventually they'll enable/disable features of AMP-based sites arbitrarily... similar to how they determine autoplay policy on their "approved sites list." Do you think Google should be the all-powerful being that determines what features you can have on your website? That's the future you're opting into if you implement AMP.