Go beyond the first stupid idea
When you speak with a designer or an innovator they often will tell you that the first idea is usually not such a great one. As ideation is a process that helps to come up with multiple ideas, it helps you go beyond our first stupid hunch.
Find unexpected solutions
By taking the time to think about a particular problem in ways you often end up with unexpected solutions. These solutions offer bring a set of new benefits. They can solve the problem with less budget, bring a fun element that is a big differentiator against your competition, or just be much quicker to implement than your first initial hunch.
Be sure you explored all solutions
When your boss tells you: are you sure this is a good idea? You often don't really know how to convince him. Now imagine you tell your boss: "I explored 300 ideas, we selected selected 30 to test, and from those one this is the one that works the best". Wooo, that's some convincing shit there. Good ideation, followed with good selection and testing, helps reassure managers, decision makers and investors that you have explored all possible solutions. Or at least that you explored all what you could explore in the given time frame.
Wow, so looking at these benefits, ideation is a holy grail? Right? Let's not get too optimistic here, and let's explore the dangers of badly done ideation.