I had same thought & said exactly same in Spoilers Thread of Chapter 1010
Also another Hint is that Zoro needs to make Three Blades Black & coincidentally his Willpower Manifest into Trion Demon
Which recently Zoro showed alongside CoC which should be no coincidence
It's a Hint that Zoro can put his CoC into Three Blades, not just One
It's basically a Choice that Adv CoC Users can Make, it's whether to keep using Adv CoC themselves or put it in their Blades making them Permanently Buffed & Imbued with CoC
This could also be the reason Oda removed Shusui & replaced it with Enma
Which is also the reason, Oda didn't give Oden Black Blades, because Zoro needs to learn how to Forge one so Oda kept Enma White
Which is also the reason Oda made sure Zoro doesn't face Kaido at the start alongside Luffy
And this is also why Oda haven't given Zoro Basic CoC before, it's because he wants to differentiate him from Luffy & give them separate Paths
I'm confident Shusui could have truly hurt Kaido & now Zoro must learn to forge Enma Black instead
IMO it should happen at same time with ZKK