The purpose of the financial section of a business plan is two-fold. You're going to need it if you are seeking investment from venture capitalists, angel investors, or even smart family members. They are going to want to see numbers that say your business will grow--and quickly--and that there is an exit strategy for them on the horizon, during which they can make a profit. Any bank or lender will also ask to see these numbers as well to make sure you can repay your loan.