No, I can't say I understand it fully - but if the clock goes backwards, peers will not talk to a client again until I restart the other peers' wireguard services. No matter if the client's clock is subsequently correct.

For some people, all their network access goes over wireguard and that includes time syncing. That's not the case for me, but for those people if wireguard isn't working their clock can't sync.

That GPS receiver looks cool! However an RTC and a battery will do just fine for me, which is the plan.