Linux

All these things still exist with Systemd. They are just called Systemd dash something

Although you're right that's not that "cut and dry" there's a lot integrated and baked into the systemd core. Even if you consider a "systemd dash something", let's say systemd-networkd we're suddenly talking about a single efficient daemon that covers all networking from basic IPv4 DHCP to IPv6 (with all it's possible addressing schemes), can act a client or more like a typical router acts, delegate stuff and manage the entire thing from top to bottom in a cohesive way.

Just think about the amount of crap you've to setup to have a system do dual stack networking and provide prefix delegation on another interface, with systemd it's just systemd-networkd. From the basics to serve IP's, the classical isc-dhcp can do both IPv4 and IPv6, however...

the ISC DHCP server can only serve IPv4 or IPv6, means you have to start the daemon twice (for IPv6 with option ”-6”) to support both protocols.

Or you'll just find you the implementation is bad and you'll run wide-dhcpv6 instead. And then you won't survive without radvd for router advertisements etc.

If you are a fan of Systemd, it is probably because you like the standardization and the integration across previously disparate services. That makes sense. (...) Obviously Systemd was a big leap forward in init.

Exactly, systemd solves tons of painful issues and provides a cohesive ecosystem of tools to manage Linux systems. While there are other great alternatives none as are complete and solid as systemd.

If you think it is making your system faster or lighter

But it may. By not having to deal with bunch of poorly integrated tools such as dhcpcd, dhcpv6, radvd, chrony, NetworkManager, resolvconf, logrotate and others we might actually have less overhead. And I'm not even talking about the time we don't have to spend making sure all those integrate properly learning 234 different configurations syntaxes and dealing with specific bugs that only happen when program X interacts with program Y with feature Z enabled.

I'm not saying system it perfect, because it isn't but it sure provides a LOT of piece of mind, stability and makes Linux a lot better than it used to be with init and friends.

I've yet to find a use-case for "making my system lighter" by exchanging a daemon that takes <0.1% of my total system memory for a bunch of poorly maintained bash scripts.

because we all know that routers have so much RAM that installing DNS, NTP, mounts, session, log management isn't a problem? something doesn't add up...