Indeed. But at that point you have a DSL which is no longer obvious when one only knows about shell scripting (eg. I have no idea what `pexp="smtpd: \[priv\]"` does), so using a completely declarative language with a trivial syntax doesn't seem a huge issue either.
One may think about systemd's unit files as a set of shell variables that gets sourced by the real script.
One may think about systemd's unit files as a set of shell variables that gets sourced by the real script.