Just being able to treat period tasks the same as I treat long-lived services, and never having to think about crontab vs cron.d vs cron.hourly vs /etc/crontab, has improved my quality of life dramatically.
I also use systemd-timesyncd / networkd / resolved on most of my systems, but in places where I've wanted to not, swapping them out is as easy as swapping any other services (looking at you, rsyslog and syslog-ng).