Curve’s foreign exchange fees are very opaque. When you have been charged an FX fee, e.g. the 0.5% charge in USD/EUR, nothing saying so is displayed in the transaction. Every other card I own is transparent in the transaction details as to what FX surcharge has been levied.
More concerning, the amount displayed in the “you saved approximately £x in fees” doesn’t change, even on weekend days when a surcharge is being applied. It appears to be a flat calculation of 3% on the transaction value. This is deceptive, as people may be relying on that statement to determine whether to have used Curve or a competitor, and potentially something that could get Curve in trouble with regulators in various countries.