1. Because it is a way of representing the context where your niche solution gives value and that’s important for your sponsor or potential sponsor.
2. Because it helps you understand what others are doing, especially your competitors.
3. Because by analyzing your competitive environment you can learn to better detect the real behavior movements of your user.
4. Because it promotes you to think in terms of uncertainty, future options and reviewing where you are leading your company.
5. Because it will help you find where your market fit or to know where your product should go to fit in a market with relevant volume.

I would like to come up with 10 reasons, can you think of any one else?