It's true, it's not only an init system anymore, it's also a service manager, a network manager, a DNS cache and resolver, a proper logging system (as in, with metadata, all in one place) and more.
Despite being opposed to it in the beginning, probably because it was immature at the time, I grew to love it even on Gentoo - my desktop and server OS of choice - which gives you OpenRC as a fully supported alternative:
- on my desktop, laptop and work VMs, it just works, with varying adoption of its components and services started, lazily activated if unneeded
- on my server, it simply makes sense for service auto-restart: OpenRC still requires you to manually enable support for service auto-restart ( https://wiki.gentoo.org/wiki/OpenRC/supervise-daemon#General... ), a feature that comes built-in in systemd and without extra complexity or components, and with predictable outcomes given the unit file
- almost all modern DEs rely on systemd, because it generally improved their session handling, sandboxing, brought user (rootless) services and other features
And generally, I think the biggest win is creating a system service management platform that can be used by all distros in the same way, without having to know 5+ init systems, having different scripts for the same service for each distro. I can basically work on my own devices, on work devices, on cloud VMs, on IoT devices, and have the same behavior, across different distros and hardware.