Nope, no reason at all. Just make sure it's out of drafts, but you have to do that with cages on tables too. You can use the floor, set your cage on a table or build a stand out of cubes. That's the nice thing about C&C, the possibilities are endless.
Just a thought for you. If you put your cage on a stand you can store your supplies under it. It might not matter to you, but sometimes when your cage is large that extra storage is nice.