Re: "It solves a problem that people have."
"What actual benefit does systemd bring?
I can only speak from my personal experience, but I have to say that quite separate from the improved startup times, the new shutdown duration is also a great new feature.
A lot of people poo-poo the decreased startup times, which in many cases are only a fraction of a second faster, saying they're really not that big a deal. But these people are forgetting the big picture, which is rebooting - you need to take both startup AND shutdown times into account.
For instance, take my laptop running xubuntu 14.04: I'd issue a 'sudo reboot' and 15 seconds later it would have completed the reboot sequence and be at the login screen waiting for my input.
This is a huge waste, because when I type 'reboot' I'm usually doing it because I'm about to go make coffee, which takes 5 or 10 minutes. So if making coffee takes 5 minutes then there's 4 minutes and 45 seconds where the machine is just sitting idle!
OTOH, when I "upgraded" that machine to 16.04 with systemd, I found that the shutdown process was suddenly taking 5+ minutes. So after upgrading I'm now able to go make that coffee, secure in the knowledge that the machine isn't sitting idle and being wasted. Also there's no risk of me typing in that reboot command and then getting distracted by a machine which shuts down too quickly, causing me to forget to make that coffee.
Systemd truly is a boon for coffee lovers everywhere.
"Why does it take so long to do this task that used to take literally one second?", I hear you ask, in your whiny, perfectionist, nitpicky, aspie, "expects things to improve rather than get worse" nerd voice. And I'd love to tell you the answer. But since there's zero feedback or log messages of any kind that I can see during this delay, and the system doesn't respond to anything (e.g sysreq hotkeys) during this time, I still haven't managed to figure it out. I suspect it's something to do with network mounts. I would spend time looking into why I have this amazing and exciting new 300+ second delay, but there was apparently a plague of locusts some time between 2014 and 2016, and they've absolutely decimated the field where I grow my fucks.
Interestingly, devuan lacks this...uh... "feature".
So to summarise and and to directly respond to your question: systemd brings coffee, because we now have more time to make it while it spends 5 minutes unnecessarily doing god-knows-what during shutdown.