If you don't choose a breakfast platter, then your counter service credit can be used for a breakfast entree.
For example, at Old Port Royale, you could get the Adult Breakfast Platter - eggs, bacon, sausage, potatoes, toast OR you could get the French Toast with bacon OR the Mickey Waffle with Bacon and Fruit Topping OR the Mickey Waffle with Fruit Topping OR an Omelet OR... well, you get the picture.
Know something? Just go up to the counter or cash register (depending on CS facility design) and say, "I'm on the Dining Plan - what can I order?". The Cast Members are EXTREMELY helpful.