To be honest, I had never heard about this product before. So I did a quick research what it is to check if I want it (just love to try out new stuff!) and decided I don't.
1. I don't really see the deeper sense behind it - I can do runouts perfectly fine with my normal royal icing which is simply made of 3 ingredients, powdered sugar, powdered egg white, water.
2. Both meringue powder and Color Flow contain a lot of chemicals which I don't want in my icing if I can help it. Especially CF with sodium lauryth sulfate. That's a thing used in shampoos etc, to make more foam and reduce the surface tension of water. It is said to cause skin problems when you are sensitive. I am very surprised it is even edible...
3. Cream of Tartar in MP is used to keep the stuff more flexible/cohesive while piping, more stable, as far as I know. Whereas Sodium Lauryth Sulfate in CF is meant to reduce exactly this, in order to have a smoother, shinier surface of your runout. In adding cream of tartar to your color flow mix, you have combined two materials which are supposed to achieve opposite things as I understand it. But maybe I am mistaken 
I suppose you will find it harder to pipe intricate designs with color flow, as it is not meant to hold it's shape, but otherwise there will probably not be many differences to royal icing with meringue powder.
If you want a weird thing like a minor hazardous shampoo ingredient on your cookies, well, that's a different question. Wilton suggests removing decoration made with it and re-use it...
I'd be interested to hear other people's opinions about this stuff, maybe with a bit more chemical understanding than I have.