Whether an appliance OS uses SystemD or not is as silly of a concern as “does the lead developer prefer cheddar or brie”
What about performance characteristics? Recoverability of workloads?
I’m interested in a FreeBSD base OS because it seems ZFS is better integrated and ZFS has a lot of incredibly useful tools that come with it. If Bhyve is at least nearly as performant as KVM, I’d be hard pressed not to give it a whirl.
It's not silly at all.
I've been repeatedly burned by systemd, both on machines I've administered and on appliances. In every situation, the right fix was either "switch distros" or "burn developer-months of work in a fire drill".
In fact, I just decided to go with FreeBSD instead of proxmox specifically because proxmox requires systemd. The last N systemd machines I've had the misfortune to touch were broken due to various systemd related issues. (For large values of N.)
I assume that means anything built on top of it is flaky + not stable enough for production use.