If you don't have any other card in your MB WAY app associated with the mobile number you use with your moey! account, you don't need to do anything. Your moey! account has all MB WAY features without needing to associate your physical cards.
If you have other cards on MB WAY app associated with the mobile phone number that you registered on moey!, to ensure that funds are received on your moey! account you must associate your moey! card in the MB WAY app, setting it as the default for transfers.