Merchant Keypad enables you to take Sale, Refund, and Auth transactions on the while allowing customers to interact with Clover Mini. Merchant Keypad can be used as a merchant-facing device and Clover Mini can be used as a customer-facing device throughout the entire transaction.
Merchant Keypad is a great accessory if you would like speed up transactions and primarily perform transactions through the Sale app and Refund app . You are still free to use Clover Mini as a merchant-facing device to take other types of transactions and use other apps.
Reference Site: https://help.clover.com/faq/whats-the-difference-between-using-merchant-keypad-app-vs-not-using-merchant-keypad-app/