Forget about the rays if you wish.
Oda cannot grant a visual effect, which we have seen on many occasions and have not been able to know what it means, to a Power Up that already has its exclusive and perfectly clear visual effect.
What you propose is illogical. It cannot be that the same effect on some characters means one thing and others another or nothing.
And this not only applies to Zoro, in the confrontation between Luffy and Lucci we also see those rays and I don't see anyone saying that Luffy used CoC. The same for Kaido when he knocked out Luffy in the Capital for the first time, there are lightning bolts, but not trails and we know that the first attack Luffy saw with CoC was on the roof.
I just limited myself to what the manga says.
Luffy wants to learn to hit without touching and we see how he does it with the example of the tree. And Luffy wants to learn to hit without touching to damage Kaido internally by skipping his scales. And as we see in the tree, it is clear that when you hit without touching there is internal damage.
But, there is a step further than Luffy if he is able to use it than introducing his CoA into the enemy.
Really, Haki is not that bad, it is quite easy if we ignore Marine Ford and the rays that I have never been able to understand.
I also tell you that maybe it is wrong to call it advanced Haki, it is something that makes sense for CoO, because in the end it is the same but for longer, but in CoA and CoC I think they are simply different techniques.
This justifies why Zoro learned to use AdvCoA and AdvCoC before the "basic" uses.