for those of us who rarely choose Marriott chain the real benefit is to have Gold status after 10K spend without staying 50 nights a year.

Also, promotions by both brands are different, and it is not clear which promotions one would be eligible if carrying RC card or if one could switch back one's account to Marriott from RC once credit card is approved. It is clear that the same person can only have one account - so it is either or (per T&C of MR), but it's also mentioned that the same person can have both cards, so it is still not completely clear to me how one could earn both types of points, but only "receive communication" from one type of brand and how often one could change preferences. They should really allow promotions to be valid through both brands.