The significance of cross-platform compatibility in software lies in its ability to allow applications to run seamlessly on various operating systems and devices. This broad compatibility enhances user accessibility and experience, meeting the diverse needs of users on different platforms like Windows, macOS, iOS, and Android. By broadening the potential user base, cross-platform compatibility can also lead to reduced development costs and increased market reach. It allows developers to create a single codebase for multiple platforms, fostering efficiency and faster updates.