You’d also need a Select account with Santander in order to get the World Elite card, which requires the account holder to pay in at least £5k a month. So the financial commitment is there, it’s not just a case of £15 a month.
Or the world elite card with HSBC Premier, which requires minimum of £75k annual salary + mortgage with them, and with a £195 annual fee.
That’s why the above world elite card issuers are able to provide unlimited free lounge access with LoungeKey.
For just £15 a month, Curve would be making a huge loss if they decide to provide the same level of access …