What do the prices of the hotel look like in comparison to before this offer?
I would imagine that this "discount" just ends up being factored in one way or another...
For comparison, a garden view room at the Yacht Club (or Beach Club, or Boardwalk) in mid-August shakes out to just over $600/night after taxes and fees.
A room-only discount of, say, 25%, would amount to a savings around $150 per night -- the same "savings" offered by the dining offer, except of course, you're forced to spend the dining offer monies at Disney restaurants, and to book a 5-night or longer room-and-ticket package at full price.
My family has already saved more than the value of that offer simply by renting DVC points for 3 nights at the GF (cost of $400/night, a $275/night savings over rack rate), and buying 3-day PH tickets from an authorized reseller instead of as part of a package (additional savings of $200).
Our upcoming August stay is split, with 3 nights at the Yacht Club booked direct through Disney, and 3 nights in the aforementioned GF DVC Studio Suite, so we aren't remotely eligible for the dining card offer. If Disney doesn't follow up with a room-only discount that actually applies to our Yacht Club leg, we may go elsewhere for those 3 nights instead, as we did last time this happened ("this" meaning no applicable discount for our dates), which would save us even more.