https://www.nationwide.co.uk/support/support-articles/manage-your-account/credit-card-cashback I can see from your image that you apparently get more, but you can see from the above link that this isn't typical. For whatever reason, Some cards are loss leaders, I agree - the Natwest Reward Mastercard is an obvious example of that (they'll lose at least 0.7% every time you use that at a supermarket). There's nowhere near as many today as there were even a couple of years ago though.
Not sure why you insist on 0.25%. OK, about the 1% I cannot access my own statements right now (Nationwide gave me a new card recently due to fraudulent charges and for some reason I can't access the old account history - still waiting to hear back about that), and as I use an Amex for a while now, it may have dropped and I did not notice. But I did log into my wive's account to make sure before I did my previous post and, unless my math is very wrong (which is not), she currently gets 0.5%. And the idea is that cards can lose money on cashback. In fact when I am in the US I get at least 2% on everything and 3-5% on many things and they are certainly losing money on that (as retailers usually pay in the order of 1-2% of transaction fees), but their business model is lure with cashback, make it back from interest/fees etc.
You don't get 1% and your wife doesn't get 0.5%, if you both have the Select Credit Card you both currently earn 0.25% (unless you've signed up since January, in which case you'll get nothing). https://www.nationwide.co.uk/support/support-articles/manage-your-account/credit-card-cashback If you were receiving 1% cashback Nationwide would lose at least 0.7% each and every time you used the card due to the Interchange Cap that started a couple of years ago.
I use it for fuel at asda - hardly shop in the store got enough vouchers for two tank fulls of fuel - I'd say that's worth it
Huh. It is a select card, which gives 1%. My wife's who got it after me gets 0.5%. But you are right, they no longer give this sort of cashback for new signups, the best I see available is 0.5% on an aqua (I also have that), so for ASDA it is indeed the best deal, even at an unspectacular 1% (unspectacular especially compared to the 5% my US cards give me on groceries at the other side of the Atlantic). I stand corrected.