It's all about the functions of different features. While backup in RouterOS provides information security, import and export bring about practicality and a dramatically increased productivity.
Unlike backup files, exported .rsc files are unencrypted and editable. Therefore, as long as you're not handling any sensitive data and confidential information, editable export files can be used for a number of purposes.
By exporting the information of one router, modifying it accordingly via a text editor, and importing that modified information into other routers, one can easily carry out projects such as mass configurations, RouterOS branding, integrations, and so much more.