well, it never has come with the plus dining, so don't know why they would add it now? Originally, there was plus dining, and then there was deluxe dining...and it came with the deluxe, but not the plus. I suppose because "deluxe" meant lots of meals, snacks & beverages for the $$$.
Now they have the quick service -- which is 2 quick service & 2 snacks for $30. Not a very good value, IMHO. I suspect they included the refillable mug to make it appear to be a better deal.
We've used both the basic plus dining and the deluxe. Never used the refillable mug while on the deluxe, and never wished we had one while on the basic. We were full all the time with both plans.