I assure you they are not.
The sprinkles need to already be mixed into the icing.
I am currently baking a delicious Funfetti cake which I am taking to my Mom's friends house.
I'm sure most people will be bringing "homemade" type items.
But be honest would you EVER turn down a piece of Funfetti cake w/ Rainbow Chip icing?
I mean sure the cake box and icing cost under $5 but what comes out of that oven is as good as gold.