There are significant security/reliability improvements all over the place. E..g. logind actually works as promissed, which none of the clones do as they can not have the necessary infrastructure that is provided by other parts of systemd. Or udev using systemd-pid1 to start services: That fixes a well documented problem with udev starting services itself -- which most non-systemd distributions do till today. Problems do notngo away by ignoring them.
Checkout non-systemd distros, most of them still use group based access to devices a user needs to run wayland. Of course that does not matter at all for X11, security is so poor there anyway.
Just use a distribution that uses the init system you want to test by default. The init system is a pretty central piece of infrastructure in todays unix, ditsributions need to invest a lot of effort to make it work well. The default init system always works better than any other options a distribution offers (if they even over options).