You do not have to ask yourself that in OP either since it ultimately does not fucking matter.
Chakra in Naruto became infinite. If its used or not was no longer of consequence, unless plot, lol.
Bleach Reiatsu had an on off switch for relevance.
Ki, Stands and Nen and probably the rest too, but idk, are baseline to use abilities. Haki is not. You compare apples with oranges here.
Any ability in HxH needs Nen. DFs in OP do not need haki.
Ki from Black Clover would be a suitable equvivalent.
And guess what! You do not know when that is used either unless its spelled out.
But if you really care then simply assume CoO & CoA are always used. You can do that for CoC too since it would not change a damn thing except ruin your pl phantasies.
But it matters.
Haki was a one of the plot point of the timeskip, and since the return of the timeskip it is the key to all important fights. So yeah it matters.
And if it is not supposed to matter why created it?
Luffy needs Haki to used G4, Zoro needs Haki to be in King of hell mode, Sanji needs Haki to use Ifrit Jambe…haki is the official counter to devil fruit power and as I said above it is the key to the most important fights after the timeskip.
So yeah one does not need Haki to fight but haki moves the plot foward which is why it is essential to understand how it works and when it is used.
And guess what Black clover is a bottom of the barrel shonen manga.
I should not have to assume anything, it should be clear. One piece is a story using a visual media, therefore, at first glance, I should be able to understand what is happening on panel.
This have nothing to do with powerlevel but with basic storytelling.
