A rich client platform is like a special computer that helps other programs work better. Imagine you have a big box of crayons, but they're all mixed up and it's hard to find the one you need. A rich client platform is like a crayon organizer. It helps the crayons work together nicely and makes it easy to find the color you want to use.
Similarly, a rich client platform helps different software programs work together in a nice way. It provides a common set of tools and features for the programs to use. This way, the programs can communicate with each other easily and share information. It makes things easier for developers because they don't have to start from scratch every time they make a new program.
At the same time, a rich client platform also makes things easier for users because it provides a consistent interface across different programs. For example, if you're used to using one program that's built for the rich client platform, it will look and feel similar to other programs that are also built for that platform.
Overall, a rich client platform is like an organizer and a helper that makes it easier for different software programs to work together and for users to use those programs.