I've been lurking here a short time now, so mine may not be the opinion you want, but here it is anyway:
As with all assessments and declarations, the main use would be to put taggable aspects on an opponent to aid you in a fight. In these cases, by identifying weaknesses in their fighting styles or choice of weapons.
Beyond that, you could use them to gain information about an opponent. You might identify their fighting style and even the school or master who trained them, giving you a clue about a mystery opponent's origins. You might recognize the provenance of a rare weapon. You might deduce that an opponent who only uses "soft" styles follows a pacifistic code and won't initiate an attack.
Also, if dealing with a particular subculture, you could use such declarations to demonstrate your own character's knowledge and therefore their worthiness to be taken seriously. Or you might put out a declaration related to a code of honor, allowing you to manipulate a social situation. You could boost an Intimidation attempt by demonstrating a knowledge of your opponent's weaknesses; this could help you win a "battle of wills".
And, if nothing else, it makes you a master of kung fu trivia.
