I am a Linux user, but I don’t really know how most things work, even after years of casual use on my Main, I just started getting into Devuan and wondered then, what exacly does systemd do that most distros have it? What even is init freedom? And why should I care?
In a very basic description, systemd is your system schedule agent. It’s the component that kicks things off in order so all the vital parts start in order so they have the other parts in place before they load.
It’s reputation is muddy because it’s doing more than a single task and old fashioned thinking is that system components should only do one thing. It’s easier to configure but harder to understand than the older init