As noted this is nor1 at work - not Marriott. If you search on nor1 over in the Hilton forum, youll see that they've been at this for years. All I can say is, if you see an offer that appeals to you, go ahead and give it a go - depending on how full the hotel is, you may get the "upgrade"/"upgrades" you've selected. It all depends on if you see value in what they are offering and how much it costs.
For me, these offers were most annoying when I've booked on points.
David