The 5us inaccuracy is basically irrelevant to NTP users, from the second update to the Internet Time Service mailing list[1]:

To put a deviation of a few microseconds in context, the NIST time scale usually performs about five thousand times better than this at the nanosecond scale by composing a special statistical average of many clocks. Such precision is important for scientific applications, telecommunications, critical infrastructure, and integrity monitoring of positioning systems. But this precision is not achievable with time transfer over the public Internet; uncertainties on the order of 1 millisecond (one thousandth of one second) are more typical due to asymmetry and fluctuations in packet delay.

[1] https://groups.google.com/a/list.nist.gov/g/internet-time-se...