In attached screenshot, all the attributes to assign to the Subnets tab: Network info and many optional pieces: VLAN ID, DNS servers, IP range etc. What Customer proposing is to add NTP servers to this structure, as that is considered a core network function these days (and NTP is usually part of IPAM & DNS appliances like Infoblox).

That way when a machine gets provisioned, like when DNS is configured as part of the Kickstart process, NTP can be configured out of the box too. In modern environments, NTP (especially where IPA & AD play huge roles) is a critical part of the infrastructure. From a functionality point of view, it would be much more beneficial to customers to have defined NTP lists as opposed to everyone repeating the same work using Puppet.