The headline here is somewhat misleading. The court already blocked tabulation of the relatively tiny number of ballots affected by the policy change before the November election, so this is just confirming the rule that was already followed in Virginia on election day.

The court here just approved a consent decree Virginia's elections board had already agreed to. The practical effect is that they can still use the USPS barcode to establish a ballot was mailed by election day when the envelope has an illegible postmark, but can't just rely on the voter's signature date if there's no postmark at all.

This is the correct result. But it's the rule that was already followed in November.