It's not that great of a deal, but for a large family it can still be a decent savings. We travel with 4 of our "kids" (they are all teens or adults) so this deal can easily save us $700 or more depending on how well we plan the use of the credits. We booked this deal in 2016 but ended up getting a PIN code for 15% off room & tickets plus free park hopper option on the tickets. We always get park hoppers so the PIN code ended up being the better deal for us (saved us over $900). We were already booked for June 2018 and our TA was able to modify our reservation to take advantage of the Summer Meal Deal. I'll be shocked if we don't get a better deal in a few months. But if we don't, I'll still be happy with saving $700+ on our food costs for the week.
I don't think they've released all of the room discounts yet. I've only seen actual room discounts (not talking about the Summer Meal Deal as that's specifically for Value resorts only) through June 10. We've traveled to Disney the 3rd or 4th week of June numerous times and in my experience, the discounts for that time period (June through August) don't usually come out until late March or early April. The Summer Meal Deal has been the exception the last 3 years...but it never ends up being the best discount for that time frame or at least it hasn't for us.