I know we've deviated a bit, focusing on the OP's SPG vs. Marriott discussion. But back to the gift guide...

I've only participated (extensively) in one other program that has a merchandise guide: Diner's Club. Perhaps some of my other programs do it, but if they do it's low-key: even lower-key than this Marriott offering.

As anyone who has participated in Diner's Club can attest, the merchandise redemption values are always bad when compared to other awards. But at the same time, I think most Diner's Club members do look forward to getting that catalog every year, and I imagine a larger percentage than we think actually do redeem something out of it once in a while. They would think the program was less robust if the catalog went away and they could only get miles, points, and their annual fee credit with their points.

I know Marriott is a different beast - it exists first and foremost to reward hotel stays and issue awards in the form of free nights. But perhaps Marriott sees adding the merchandise component as a way to make the program more robust and rewarding to their "super Platinum" road warriors who might care less about value-per-point and more about other options besides more nights away from home. If you are on the road 200 nights a year and have a bottomless pit of MR points and FF miles, a free HDTV courtesy of your favorite hotel chain starts to look pretty good...

I just look at this as another option - even though it's one I'll never use. If it makes enough super-Platinums happy, it's worth it to Marriott.