It is a card specifically offered to Japan with slightly different benefits. One of them is the promise of an automatic upgrade in medallion status to Silver/or your next level (most Japanese people probably aren't even program members to begin with, so this entices them to join and just make FO probably. If they did this in America, everyone would be Diamond within a week...)

My Delta page does say Delta Amex holder now, and pay with miles was enabled. But that's the only change so far.