Comment # 1 on bug 1231244 from Franck Bui

(In reply to David Cassany from comment #0)
> Udev package provides the setup of systemd-timesync user in
> `/usr/lib/sysusers.d/systemd-timesync.conf`, however this user is not
> created as part of the installation.

Any changes in /etc are delayed until the first boot.

One goal behind it is to support for stateless systems. Another reason is that
it also matches the behavior you would face on transactional systems during
package installations at runtime. In this case changes in /etc are not
available until the system reboots.

Not sure why `system-user-*` packages don't do the same though.

Is the consistency of system user creation your only concern or do see other
issues ?