If you are trying to get a very popular restaurant, and / or time (ex. Crystal Palace 8:05 breakfast, Cinderella's Royal Table, Rose and Crown in time to watch Illuminations) you might well be out of luck. If you have some leeway in where you eat, and / or the time, you will be fine.
I think I love you

Great job spotting that!
Traditionally, you would get great pictures on Main Street, and even by the castle, with almost no one around, then get your breakfast, and still be at the front of the crowd for rope drop. Now, well, not so much. Main Street will have plenty of people. Getting Castle pics with no one around isn't likely, and by the time you get out of breakfast, there will already be a crowd lined up waiting to go into what ever land you are headed for.
That having been said, if you are going to Crystal Palace for the food, the interaction with the characters, and because that breakfast in the park is a lovely way to start your day at the Magic Kingdom (and these are the reasons you SHOULD be going for breakfast at the Crystal Palace PPO) then by all means, carry on, you will be getting out of the experience exactly what you expect to!
It is always nice to get that early breakfast. To be honest, I can't think of a better way to start a day at the park!