Some people don't like systemd because it rolls a bunch of other functionality beyond 'just init' into a giant monolithic beast. The advantage is that distro maintainers are able to present an extremely usable and stable system like Ubuntu, Arch or any of the other mainstream distros. For most people that just want to use their computer to do regular stuff like browse the internet and edit photos and stuff, systemd or otherwise doesn't really matter because you pretty much never need to touch those parts of the system. Alternate init systems are for power users or people with particular constraints. For example, one of the reasons Alpine Linux is able to be so small is because it uses OpenRC instead of systemd.

Personally, I use a non-systemd distro because my computers all have tiny-sized HDDs by today's standards and I hate having to read a bunch of documentation every time I want to create a new system service. To me, it's easier to just write an ordinary shell script. I don't need all the ridiculous logging capabilities that systemd offers. Regular old plain text is enough for me.