Ah I got lost in the gobbletygurk.
Probably won’t work but can try…
OSkills = item Grants a skill as if you had it on your tree & access through skill allocation.
Feel free to cast this skill.
WW/WB - Specifically restricted(and recently allowed to cast a few skills from their own tree)to being unable to cast spells. This has always been a mechanic.
CtC = Property of an item. Conditions must be met for it to “cast” - striking, being struck etc. Primarily melee and on-hit/on-death and so on.
CASTING cannot cause CtC in most circumstances(all? idk if there’s even 1). (ie. WW is considered a Cast Ability + some other skills I cannot recall cannot natively trigger this or do so at a reduced proc % rate).
Should WW/WB be allowed to Cast oskills - any and all skills - that’s the question and debate.
CtC - again: Non Debate. Apples. Oranges.