It seems you can double dip the “get more 50% promo” with this 30% one. Flyertalk Members have been successfully registering for the 30% offer then adding on the 50% offer. Remember the 50% offer is for first time transfer people only.
If you apply for the Platinum card from American Express and use that 50K bonus to repay your original 50K points advance from American Express you end up with a whole ton of Delta miles (90,000), lounge access, Silver status for two years and a $200 incidental credit on your favorite airline all for $450.
Rene describes the steps better than I could in Saturdays post so go back for a reread. Just remember to register for the 30% offer first then follow Rene’s instructions.
And here is the card for the 50,000 Membership Rewards Points.