Answer:
Benefit 1: The opportunity to own a market
The US government protects your invention for 20 years, that means that during 20 years, you virtually own your invention's market, e.g. Eli Lilly patented Prozac in 1987 and they held the monopoly fro 14 years until 2001.
Benefit 2: Attracting Investors and Funding
Who will risk their money if an invention is not protected? Investors don't care about good intentions, they care about money, and the only way an invention can guarantee a return is through patent protection.