Neither Square or Toast support PIN entry, whereas a Clover (made by First Data, the largest processing platform) and Ingenico/Verifone equipment have the proper hardware to ensure physical security while they encrypt the PIN in transit back to the bank your platform uses to process the transaction.

PIN Debit transactions are less expensive to process since there is less risk, but it adds complexity (First Data has many different bank keyloads like Carlton 500, Wells 350, etc depending on the bank that is underwriting the chargeback risk for your account if your company folds).