Debian is a 30-year-old, complex operating system that aims to be a high-quality, secure, general-purpose OS consisting of free and open source software. Unlike other distributions that focus on specific purposes, Debian strives to be suitable for most people for most purposes. The project has a democratic governance structure with a project leader elected annually. Debian follows the Debian Free Software Guidelines, which provide clear rules for what software is accepted. It insists on being self-contained, not relying on third-party repositories, and avoids using bundled libraries to simplify maintenance. Trust is an important aspect of the membership process, and Debian assigns code names to its major releases to facilitate mirroring. Change in Debian is gradual due to its massive size and the extensive work involved.
https://blog.liw.fi/posts/2023/debian-reasons/