No, in order to use Green P Mobile Pay, you must load at least one payment method onto the account using a credit card, Apple Pay/Google Pay or a PayPal account. Once the account is loaded, you can remove your credit card or PayPal information from the account.
If Apple Pay/Google Pay are the only funding source, then you cannot remove this. Note that you would have to validate a purchase through Apple Pay/Google Pay via authentication. If you add another funding source, then you are able to remove Apple Pay/Google Pay from your wallet.
By retaining the card number/account information in the system it provides a more convenient means to add funds to the Green P Account.