The main reason for this is not having to deal with systemd, which lets face it, drives a coach and four through the notion of doing one thing and doing it well.
It operates on the "do it our way or get stuffed" principle which is anathema to those of us who like to get stuck in to the internals of linux and the boot process etc.

"They have taken what was clearly a rats nest that anyone who needed to could ferret their way around and set up to suit themselves, and replaced it with something 'everybody can use', but which few actually understand or have any meaningful way of understanding --- we're talking about the great unwashed of Linux users here, folk who can knock up a script, maybe even do a bit of coding, like to be able to poke around and get to grips with the finer points if they need to, but mostly probably don't.

Now they pretty much can't, even of they want to. That heavy responsibility has been lifted from their poor aching shoulders, and hidden away.

Yes, systemd works, in the way that a self-appointed group who are clearly serving the interests of corporate users, want it to work---a ubiquitous service layer which is largely opaque and outside the control of the majority of users. Does it 'work' in a way that really serves the long term interests of 'free' computing. At the moment an affirmative answer is highly questionable."

(https://m.forums.theregister.co.uk/forum/2/2016/03/08/solus_linux_review/#c_2803180)

Its also a distinct flavour of linux, built from the ground up, and is fairly new, 2008 I think.
I follow the following instructions
http://www.troubleshooters.com/linux/void/quickinst.htm