The problem is when you fork your own distro you quickly discover that using systemd is the easiest way to maintain it. It isn't a coincidence that medium and small distros like Arch Linux picked it up in addition to the big boys. Unit-files save package maintainers boatloads of time they used to spend having to writing and maintaining initscripts a lot of which is copypasta boilerplate anyway but its usually distro specific copypasta.
This is the source of a lot of the strife in my opinion. The people who actually do work to maintain distros like systemd, the users not so much.