To be fair, every part of it is a small binary that generally does a single thing. You don't have to run them all or even install them but they bring a lot of necessary functionality around base host bootstrapping that everyone used to write in shell for every distro.

I find it nice as an operators of multiple infrastructures to be able to log into a Linux system and have all the hosts bootstrapped in a relatively similar fashion with common tools.

Sysv kinda sucked because everyone had to do it all themselves. Then we got sysv, openrc, upstart and then systems and there was a while there where you never knew what you'd get if you logged into a box. And oh look, I gotta remember 10 different config file locations and syntaxes to assign an IP. Different syntaxes to start a daemon. Do I need to install a supervisor or does that come with the init.

People are doing a lot of really cool stuff with Linux OSs assigning IP addresses in 10 different ways or starting programs was never one of them.

Its also not that systemd has a monopoly, there are other init systems out there, but all the big distros, RH, Debian, ubuntu, arch . . . all came to the same decision that it was the best available init and adopted it. There are other options and any one of those projects is big enough to maintain its own init, but no one really finds the value in dedicating reaources, so they haven't.