It matters for Zoros dream. In wano, the narrator implied emperors are stronger than first hand and second hand men, which would mean
Law > Zoro, so Zoro is not the strongest swordsman
If Zoro hermanos really need this to etablish Law is weaker than Zoro they alread lost this fight
Title merchantry makes sense for characters we never seen fully fight like old legends or characters they still didnt fight to the fullest (like Shanksu and his Painter apendix)
We seen law fight and we will see law fight
No one beside sword scholars gonna take someone seriously if law looks stronger "but but my sbs idolo is wss???" and vice versa and they gonna be laughed at like currently
Useless question