John Mueller Said, AMP a ranking signal? At the moment, it is not a ranking signal.” Then in his further explanation he explained that, you can use the AMP to turn mobile friendly, but still, AMP in itself is still not a ranking factor in any way.
AMP launched last to last month, but it is visible in the top news box of mobile search only. Very soon, Google is planning ahead to launch the AMP beyond that the news box- whenever it will be launched.
But until now, it doesn’t make sense of being considered as the ranking signal, until it is exploited in the core mobile web search results.