“For apps that use native libraries, 64-bit code typically offers significantly better performance, with additional registers and new instructions,” google share the news on Android Developers Blog.
Apple also dropped support for 32-bit apps in iOS 11 in September 2017.
Alphabet also wrote, 2017 has been a fantastic year for developers who have seen growth and success on Google Play. We’ve been hard at work on features (including those announced at I/O 2017 and at Playtime) to help you improve your app quality and business performance. With these features and the upcoming updates, we hope to see the Android and Play ecosystem continue to thrive in 2018 and beyond.