User blog comment:D.Dragon123/Why Haoshoku haki is useless./@comment-4605926-20130115165516

Alright then, first off I will begin by saying that I somewhat share your opinion. At first glance, the ability wouldn't likely seem much to be afraid of, if indeed that is its only use. However, I tend to believe that Conqueror's Haki has various other uses other than knocking out weak willed people. I believe that it could be used to gain some kind of edge in a battle considering your opponent (a strong one for this matter) doesn't possess the same ability.

If though, knocking out weak willed people is really its only use, let's try to look into some possibilities that make it as frightening as it is presented to us in the series (the possibilities are ranked according to their importance in my opinion):

1) First of all, as many here already said, all users confirmed to possess the Conqueror's Haki are all incredibly powerful fighters and major figures in the One Piece world. As you probably already know, Haki utilizes the willpower of a person and NOT his strength, therefore, not possessing Conqueror's Haki doesn't necessarily mean that the person is weak, which explains why as the Admirals are indeed very powerful they are probably not as strong willed as those who do possess the ability. In addition, I would like to refine the idea slightly into making it clearer as to why it is an important aspect. I believe it is the will that imbues the fear and not the ability itself. People with incredibly strong willpower are more likely to become powerful than others who are not as strong willed, hence the fear. This is also very true in real life, while even if a person is considerably smarter than another, with less willpower he will not likely reach as far as the other who is filled with the will to succeed in whichever subject that may be. Therefore, people who are seen to possess the ability are generally more feared regardless if it can harm those people or not. The fear is not for that specific moment but rather for the distant future (perhaps not so distant but still future), where the person is likely to have become significantly more powerful to the point where those stronger opponents' power and influence are being threatened.

2) Even though Conqueror's Haki can only knock weak willed people unconscious it is still a force to be reckoned with and here's why:

A. It could be used as a strategical and tactical tool in many situations where you might want to knock a person unconscious from a distance, without injuring him or maybe even for stealth reasons.

B. It requires near to no effort (or so at least it seems to) to execute which is especially useful against large crowds of opponents. Fighting an additional 50,000 men on Fishman Island would definitely have given the Straw Hats a harder time not to mention the possibility of a defeat (don't forget that Luffy's Conqueror's Haki is still considered to be relatively weak).

C. Considering a person possessing the ability is still able to fend off the masses without utilizing this ability, using it would save him much power, strength and not to mention time. It would be much cleverer to do so, unless of course the person decides not to for one specific reason or another. Just like PX, it seriously makes me wonder why Whitebeard hasn't used it in the war... Would've saved him many casualties, time AND chances to win the war.

3) Again, like many people have already stated here, Conqueror's Haki is a symbolic and rare ability to possess and should mostly be feared by the masses. When people witness this ability (the stronger ones for this matter) they automatically think of the other figures capable of this ability and are thus stricken with fear of sorts.

In Conclusion, I believe Conqueror's Haki has more uses than we are presently aware of, however, if it doesn't, it is still a force to be reckoned with because it implies that the person is very strong willed, which is a threat in itself. In addition Conqueror's Haki can be used to gain specific advantages in large battles (number wise) against enemies who do not possess the ability.