You're assuming that Meta developed the Time Card [0] because GNSS or NTP aren't accurate enough. That's not the case, Meta tells us exactly why they developed

You're assuming that Meta developed the Time Card [0] because GNSS or NTP aren't accurate enough. That's not the case, Meta tells us exactly why they developed it, in the "Why do we need a new time device" section of [0]. TL;DR: openness and software support. And they're not putting one in every server, they're using it as a reference for their new NTP-based timing protocol [1], with which they showed an uncertainty of only a few hundred microseconds. [0]: https://engineering.fb.com/2021/08/11/open-source/time-appliance/ https://engineering.fb.com/2021/08/11/open-source/time-appli... [1]: https://engineering.fb.com/2020/03/18/production-engineering/ntp-service/ https://engineering.fb.com/2020/03/18/production-engineering...