If you intend to use the account as a true savings account, beware of the withdrawal limitations:
“Apple Cash Transfers
You may deposit or withdraw funds from your Account into or from Apple Cash. Transfers must be at least $1.00 and can be no more than $10,000. You may transfer no more than $20,000 per rolling 7-day period. We may place additional limits on the amount and frequency of transfers for the security of your Account.” ( page 7 of the Deposit Account Agreement)
Note that the savings account does not appear directly in your Apple Wallet. Instead, you must open the tab for your Apple Credit Card and find a button for the savings account there. To access the agreement that I quoted above, tap the circled ellipsis in the upper right corner and then the Account Details item. Scroll to the bottom to see the Terms and Conditions button. Tap that to open the PDF, which you can then share back to your computer to read it.