Hi oceanscape
We used ours the last twice we have been. Yes you can use them in the shops just like a credit card and get cash from ATM's. All you have to remember is that you have sufficiant funds in your account otherwise the bank will charge you overdraft rates. You can contact Nationwide before you go and have an overdraft authorised if you think you may go into the red. We have both Credit and debit cards. Credit card is the just in case card!!!!
Hope this helps