In product development, a benefit is an attribute expressed in what the user gets from the product rather than its physical characteristics or features. Benefits are often paired with specific features, but they need not be. For example, the benefit of a car that can go from 0 to 60 in 3 seconds is that the driver can get to their destination quickly. The benefit of a self-cleaning oven is that the user doesn't have to clean it themselves. And the benefit of a pair of comfortable and stylish shoes is that the user can look and feel good all day long.
Ultimately, benefits are about meeting the needs and wants of the user, and that's what makes them so important in the product development process.