It all reads like DCC (dynamic currency conversion) in disguise, which normally is a rip off. I would not be surprised if this is a pre-chargable card with DCC rates available on the card owner side, as opposed to being decided in the transaction terminal. If my guess is right, then this is useless. I rather pay with my regular EB MC without using DCC. This will only be attractive if it offers better exchange rates than EB MC and DC.
Both Visa and MC have been so fa using the ability to lock the rate to screw customers; hard to see why MC would do otherwise this time. But let's see; and let me be proven pessimistic.