1 - Being creative takes a bit of planning. That may sound contradictory, but it really is true. Planning out time to be creative means you can make the most of that time and you will be able to focus on what you are creating.
2 - Keeping your ideas and plans all in one place allows you to use your creative time for just that, creating, instead of searching for the sketch or idea that you wrote down on a sticky note.
3 - Planning as a creative requires you to use your whole brain. Envisioning what you want to create, looking at what you need to create, and doing those things.