By that logic, why not bring more types of entries into the service file?
Path units for inotify triggers, mount units for NFS automounts active only when the service is running, socket units that register network triggers, all of these might have some use.
It might seem cumbersome, but I do agree that configuring complex activity sometimes means many unit files. Timer units would be a clear example.
You have identified the key point, thank you. Sometimes, things are complicated enough that you want to break configuration up into multiple units. But not always. At the moment, systemd forces you to always break it up, even when that does more harm than good.
Path units for inotify triggers, mount units for NFS automounts active only when the service is running, socket units that register network triggers, all of these might have some use.
It might seem cumbersome, but I do agree that configuring complex activity sometimes means many unit files. Timer units would be a clear example.