Agreed: they aren't even a bank and just help facilitate Samsung Pay's growth in the UK. I used Curve even before they had the Samsung Pay features: they didn't need to work with Samsung but they did, and with no extra cost for the end user, nor any bank charges... they don't hold your money until the payment is processed by the paying bank (the operations appear immediately in your pending bank operations). They also helped where a Company accidently charged the wrong amount: not only did that company refund the difference, Curve, as a gesture of good will, also paid me the same amount... without never having had my money in their bank.
Also, the rewards and cashback offers are varied and permanent for a list of merchants, including Wilko, Argos, M&S, etc.
They always put the customer first, offering is services to make purchasing as convenient as possible!