Forum:What is the true strength of Haoshoku Haki?

Besides being able to knock out enimies with weaker wills,Haoshoku haki semms to be completly uses less against stronger enimes.Luffy's ability to use this haki semms to be futile if he is to fight great pirates such as the yonko.I mean you could probably debate by saying that luffy hasn't fully mastered his haoshoku haki but have a look at shanks.When he visited whitebeard on the moby dick,yes he was able to destroy the ship to some degree but was unable to knock out stronger members like marco,jouzu etc even though he has mastered this.just some of my thoughts it could have a way stronger form