There are a lot of advantages to using git, in part because it was developed for a massive project (the Linux kernel) so it's very thoroughly tested, in part because it's exploded in popularity so a lot of a tools, integrations, and documentation are available for it. However, it's not the alpha and omega of version control. Some people prefer the interface of Mercurial, some people use Fossil because it integrates issues and wikis, others have stuck to older tools like Subversion, and still others are experimenting with new approaches like Pijul.