Honestly, remove the word digital from your question and what is the difference between a wallet and a shopping cart?
The digital wallet is what stores your payment instruments (or methods). The shopping cart is what stores your physical (or digital) goods that you are buying and intend to pay for with the payment instrument of choice in your wallet.
The digital wallet is what stores your payment instruments (or methods). The shopping cart is what stores your physical (or digital) goods that you are buying and intend to pay for with the payment instrument of choice in your wallet.