I don't know.. your application can and should be portable.. But if you want to support systemd, sysvinit, launchd, windows-services or whatever, that's up to you. It's this tiny part where you need to commit to some piece of technology.

I don't see the difference between creating a systemd config file, which is super clear and managed properly and to create a bunch of init scripts that depend on pid-files which might be stale and where those directories are abitrary.