Invoke method by dbus VS. system() in C, eg, ScreenSaver

Question

I want to use a tool in my program . eg, org.cinnamon.ScreenSaver

I can invoke shell command directly in C by using

system("cinnamon-screensaver-command --lock")

Or using dbus, require session bus, eg "/org/cinnamon/ScreenSaver", then invoke method "Lock()".

I know using dbus is more graceful in gnome than system(), but I don't know the main advantage about it.