[Aloha]

As mentioned by a parallel commenter, your link doesnt say what you think it does.

That said, the most power line synchronization is useful for is clocking not time, and to be very honest, its only a consistent clocking source in some places (who perform adjustment to ensure a long term value of 50/60 Hz), which means it can be used to provide a clock source to keep a device in sync, which already knows the time, but cant be used for cold start of a device.