It becomes easy to communicate your ideas to the people you interface with, who in turn can give you better ideas or complement the ones you have. Collect all the material to one place. Having a business plan makes it possible to have all your ideas and plans in one place. It becomes easier for you refer to it and to use it to develop your business. You become a more committed business person and even others people, like your prospective financiers, can easily regard you as a serious business person.
Why is that? The intent was there; the energy was present; and ideas were flowing. That's the easy part _ coming up with the ideas. The success of your planning doesn't rest on the ideas, but rather, implementing those ideas. It's true, companies need to foster innovation in their business planning, but more importantly, they need to create a business environment that enables team members to execute these ideas with an "on_time, on_budget" mindset. That is where the work begins.