It boils down to personal philosophy really. In the same way Microkernel vs Monolithic kernel is.
Sysv init and it's derivatives over the years relies on the 'Unix way' of little independent and autonomous scripts that are created by individual maintainers to help boot strap services using an init daemon. Init has no intelligence though and will go through the provided scripts first come first served. This can cause locks and timeouts as services try to start before other services have completed. Over the years there has been attempts to streamline this dependency hell but only to a limited effect. The init scripts became more and more complex as more a more distros started diverging in what core services the needed to start up.
Systemd took a different approach it made a smarter init daemon that could do more than just run custom scripts. It built a framework with dependency at it's core. It took a standardised configuration file which is very easy to understand and made maintainers fill out the bare minim