Not including swords I think it'd be useful for the survival aspect of the mod as well to bloom benefits like imbued tools have Eff 2 but maybe start at eff 1 when you're just obtaining that Haki. I don't know how that would interfere with tools already enchanted unless you'd just make it add on to whatever level of Eff that might be.
This could also be a small addition as a side mod if not the main project I would think.