Google details upcoming 64-bit requirement for Android apps on the Play Store
In late 2017, Google began alerting Android app developers about a 64-bit support requirement for the Play Store. The policy comes into effect this August, and Google today is providing more details about the transition.
Android has supported 64-bit CPUs since 5.0 Lollipop, and the Play Store in 2017 announced that apps using native code must provide a 64-bit version in light of future chips that only support 64-bit code.
In August 2019, the Play Console will require that all new apps and updates that include native code provide 64-bit versions. Google is not removing 32-bit support with continued Play functionality in the future.
(Score: 2) by axsdenied on Thursday January 17 2019, @04:30AM
Nope, there are non-flagship 64-bit devices. For example, Motorola G6 Plus is 64-bit and costs about US$250. Or the emulator is free if you don't want to spend anything.
And to your question which device to use for testing... probably it does not matter much, you can just use the emulator if you want.
The main point was that some apps do not work on some phones as they do not support 64-bits.