[customkitchen]

>compare systemd's timers to cron implementations sharing crontab format, or systemd journal to syslog implementations, sharing its standardized protocols. With a single interface and different implementations, you can easily swap those, but with a monolith like systemd you are mostly stuck if the software actually makes use of it.

But this still makes no sense. You can just develop another thing that converts from the systemd format to something else, or make the other daemon capable of loading the systemd format directly. It isn't even hard to do this, I've seen various things do it. And depending on where you are the systemd formats are arguably more standardized than old crons and sysloggers in the current year.