NTP service shown "inactive" with 'timedatectl status'

On an Archlinux host, I noticed that command timedatectl status returned correct result for times (local and UTC) but also mentioned that the NTP service was inactive. That struck me as odd because ntpd.service is enabled and active on that machine, even though systemd-timesynd.service is present but not enabled. On https://unix.stackexchange.com/a/542959/72707 I saw that provided the systemd-timesync.service is available, doing:

# timedatectl set-ntp true

is enough to show an active NTP service in the output of timedatectl status. I also saw that it automatically enabled and activated systemd-timesync.service. Hence my question:\ Do I need the ntpd.service at all ? Is there a differentiated need for both systemd-timesync.service and ntpd.service?