The main benefit of using responsive web design techniques is that it ensures optimal viewing experiences across a wide range of devices and screen sizes. By employing flexible grids, images, and media queries, responsive design adapts the layout and content to fit different screens, from smartphones to large desktop monitors. This approach improves user engagement and accessibility, minimizing the need for separate mobile websites. Additionally, responsive design can enhance search engine optimization (SEO) since search engines favor sites that provide consistent experiences, helping businesses reach broader audiences effectively.