Premier Rewards Gold earns bonus points in some categories where Platinum earns only one point per dollar (US restaurants, US gas stations and at US supermarkets.) Use it for those purchases.
I know that. I got the PRG before Platinum and other premium cards. I get more coverage than I can use.
Folks recommend to possibly close it in the 13th month. So the AF can still be refunded (within 1 month). And this still does not break AmEx's rule for closing the card within the first year. Not sure if this matters. I just have no reasons to use this card any more for the MR earning.