Well, there's more to combat than pure, raw skill. There's trickery, feints and deception too. If say, you're able to fire some web in BJ's eyes when you dodge one of his slashes, it's going to be really effective. Likewise, it seems like a great ranged attack to have in our arsenal since we're primarily a close-ranged fighter and our neigong only works when we have physical contact with the opponent. If we had a qi blast of some sort, then maybe we'd have a more viable ranged attack, so we need to look at other alternatives here.
I don't think it'd be too effective, he's see us bringing up something to throw and he's really fast with great perception. This stuff isn't Spiderman brand silk, it's not going to stick-- he'll be right slashing away at us while pissed off a moment later, at which time we can regret not picking up sword/unarmed skill in favor of a bonus for silk and pick-pocketing. At least we might be able to take his golden fox leaves to heal us after our defeat so that we can be whole before Zhang Jue tears our heart out.
As for ranged attacks, we have one; it's called going really fast towards our opponent before caving their skulls in with a kick. I'm not sure why you think we should need a ranged attack-- our qi actually makes us last longer only when in physical contact with a foe, so it seems to me that we should be beating on them in close range rather than flinging silk at them from a distance.
Our new neiggong vampirism works only with physical contact, as Esquilax pointed out, so that's a point against spears and swords.
For all our skill in unarmed, even Xu Jing recognized during a number of tournament fights that he wouldn't be able to win against sword-wielding opponents and would thus need to pick up his blade. Our gradual neigong sapping won't help us much if the other guy can just slice our tendons. We're going to have to fight with the sword again, I just want us to be better when we have to so that our performances with the blade don't go as embarrassingly as they tended to during the tournament.
The same reason we improve all of our techniques - to be able to do more, and be more successful with it, of course.
That's a great sentiment, but on the eave of the Orthodox challenge I really think that we'll get more benefit out of a point in sword combat than we would get out even seven stats in drinking. We should try to make our stats match up with our goals, and Xu Jing is fighting all the time even without considering the huge number of challenges we'll be putting forth in the near future. Even if we were granted nine points in drinking as one of the options I'd still go with this-- while identifying traps and setting them would a fantastic skill to have, I don't think that Jing really encounters them regularly enough to justify passing up on his pugilistic skills right now.
And if unorthodox fighters can become Great Pugilists, that means that certain unorthodox techniques are accepted if they are not outright underhanded, like poisoning. Or that there is no one willing to ask for a rematch.
Tearing someone's arm off with a cruel technique is highly unorthodox, yet it's still obviously martial arts. Tying them up with strong as steel silk so that they can't move incapacitates them is also unorthodox, sure, but I don't think it really says anything about the strength of one's kung-fu. The Orthodox schools are willing to accept the former as fighting even with a style that they don't agree with, I think the latter is quite another thing.