Ok, this might sound stupid why I listed systemd here but the reason is, thanks to NixOS and being part of it, I learned a lot while refactoring the crowdsec module and editing my config about how to work with systemd.

Also thanks to NixOS alone I started to understand how many features systemd has (and why some people claim that it sucks): Yes it has a lot of features but they are also useful!

You can

• manage your network settings with systemd-network
• prepare directories, links, files with systemd-tmpfiles
• create your services
• read the system logs
• use it as your boot manager

and so much more. It's huge!