Kali Linux is an open-source, Debian-based GNU/Linux distribution geared towards various information security tasks, such as Penetration Testing, Security Research, Computer Forensics and Reverse Engineering. - It is NOT a recommended distribution if you’re unfamiliar with Linux or are looking for a general-purpose Linux distribution.
Kali Linux is specifically geared to meet the requirements of professional penetration testing and security auditing. To achieve this, several core changes have been implemented in Kali Linux which reflect these needs.
Compared to upstream Debian and other Debian related distribution such as for example Ubuntu big differences are:
Network services disabled by default ...
Custom Linux kernel ...
A minimal and trusted set of repositories ...
It is NOT a recommended distribution if you’re unfamiliar with Linux or are looking for a general-purpose Linux Server OS or desktop distribution for development, web design, gaming, etc.
Even for experienced Linux users, Kali can pose some challenges. Although Kali is an open source project, it’s not a wide-open source project, for reasons of security. The development team is small and trusted, packages in the repositories are signed both by the individual committer and the team, and - importantly - the set of upstream repositories from which updates and new packages are drawn is very small. Adding repositories to your software sources which have not been tested by the Kali Linux development team is a good way to cause problems on your system.
While Kali Linux is architected to be highly customizable, do not expect to be able to add random unrelated packages and repositories that are “out of band” of the regular Kali software sources and have it Just Work. In particular, there is absolutely no support whatsoever for the apt-add-repository command, LaunchPad, or PPAs.
Excerpt from: https://www.kali.org/docs/introduction/should-i-use-kali-linux/