The Marriott Promos seem to be more and more targeted - I wish I had gotten those 10 bonus nights too. I am of the opinion that Plat is vastly superior to Gold in the new program. Gold doesn't get you much, Platinum gets you lounge access when there is one, breakfast at lots of brands and suite night awards which are nice, when you can use them. I've had pretty good luck with upgrades as a Platinum, got very few when I was Gold.
It would depend on how cheaply you could do the 8 nights - if you have points to burn (or a Cat 1 near enough that you can do a couple of mattress runs there), I would seriously consider it. For me, a $200 conference room would almost always be the cheapest way to get the extra nights, because there are no cat 1s near me. It would be worth it if I knew it would get me, say, breakfast for 2 people 10x next year.