You cannot search for the app on Android tablets though it is available in Google Play Store in your country. Even when you can find the app by opening the direct app link in Google Play Store, you still fail to install the app. It says 'Your device isn't compatible with this version.' 

This issue happens mainly because of the device incompatibility; in other words, the tablet specifications don't meet all the app requirements.

As you may already know, Android runs on a wide range of device configurations. Thus, some features are not available on all devices. For example, some devices may not include a rear camera such as Nexus 7. While your app's functionality requires the use of rear camera to scan cards at the checkout steps, your Android tablet is with wifi-only and just has front camera. As a result, when Google Play checks device hardware, it will mark the device as incompatible and you cannot search or install the app. 

For your reference, please refer to Device compatibility overview.