Is Google AMP still helpful in SEO?

Absolutely you should do AMP. It is not directly a ranking factor but it is indirectly for a few reasons:
People like AMP content and click on it more often. Higher CTR is a ranking factor
AMP pages load faster than standard mobile pages. Page speed is a ranking factor
AMP pages deliver a better user experience which means a lower bounce rate. Bouncerate is a ranking factor

Quote from: sinelogixtech on November 20, 2017, 06:52:12 AMBouncerate is a ranking factor

Bounce rate is not a ranking factor you are only the one stated that and its only an estimation of your site pages performance from the users.

Accelerated Mobile Pages (AMP) is out and has been speculated to have two benefits for SEO. One is it will have a "Fast" label designation on search engine results pages, and the other is that it will be a ranking factor.