Pretty interesting. As I recall with the pilot strike too, scheduling issues are a part of the negotiation. If they gave the benefit without having to have the SK FA next to them, believe this would help eliminate at least a few frustrations and the spouse could fly and be at whatever destination with them.
Of course wearing a competitors uniform onboard is quite silly and rude, nevertheless would make sense if he was just going to visit her in Rome/Nice/etc. where his FA spouse had their overnight or the like.