Implementing Google Amp on an already highly mobile-friendly website?

I have a blog type website running on a CMS I built myself. This week I implemented a feature to also deliver Google Amp versions of certain content types. A couple of years ago I saw good result with adding Amp to a rather slow but high volume website. But now I'm reading about the status of Amp in 2019 and the more I read, the more I start to doubt that I should activate that feature.

My website is already highly optimized for mobile and speed. Average window load time on first visit in the country I'm targeting is below one second, second visit below 600ms. Average site size is below 400kb. Google pagespeed insight gives it a ranking between 92 and 95 depending on the page type, yslow 98%. Over 60% of visitors are on mobile and they spend on average 3 to 4 minutes per session.

When running tests between the normal site and the amp version the only difference I see is a reduction in time until dom content loaded from roughly 400ms to 300ms. Time to window load and time to first interaction doesn't change.

So, when implementing Amp in the past the point for me the main selling point was speed. But is there an advantage for me to have Amp on a page that is already fast? Or could it even hurt me in the rankings? It's not a news or recipes or stories page. Just a blog.