There actually is a big difference! The ones you order at the podium are premad frozen cakes that are thawed daily to present to diners.The icing tends to taste a lot like Crisco from what ive heard.Also, they can't do any personalization to those cakes, like adding names.
If you call and order a cake, you talk to them and get the cake that you want, i.e. a marble cake, or a character themed cake, or writing, or all of the above, lol. The cakes are baked fresh for you by the bakery that handles your order, and they are high quality cakes.
Ive ordered one from the Yacht club in the past, and it was an excellent, gourmet cake.