Yes cash APP cards can be used at ATM machines to withdraw cash from the cash app card.
You can use your cash APP card at any ATM that you have around you although you'll be charged the regular ATM fee which is normal.
I use my cash APP card to withdraw cash at ATM machines when I need too and all you need to do is insert or swipe your Cash APP card at the ATM machine and enter your PIN number.
Then select checking for the withdraw option and then as long as you have the money in the Cash APP account you can withdraw the amount of cash you need.
I've never had a problem withdrawing cash from my Cash APP account using my Cash APP card at ATM machines.