Your LoopPay account is very secure. Not only is your device encrypted, but your account is locked by password and PIN.
Go ahead and record that security code. It’s optional and it is not required that you do, but it’s very useful in case a merchant asks for it in a store, or if you want to order online or by phone. You’ll want to use your new digital wallet in the same manner as you used your leather one. Having that security code may come in handy.