You said it gives him new power, but he still fight with kicks. RS is not for power, only disguise and stealth missions. He trained even without and with RS.
Enma is magical weapon anyone on Haki level can use.
Yeah and that is why if you give it to someone like Luffy, he does more than Zoro, but even so that more Enma's abilities, not Zoro.
You didn't answer my question on why his other swords didn't get into scales of Kaido then?