Earlier quoted context omitted.
This story seems really weird by modern standards. The silk washer gets a great deal. The traveler could likely have offered far, far less because the value he saw wasn't obvious at all to the silk washer. Traditional storytelling would probably have suggested that the silk washer was naive and suffered for it, but he comes out great in this story. The traveler takes a huge risk in assuming this will prove to be a hu…
Simple. Think big. He valued it enough to know about naval problems to know its huge value, and wasn’t unfair and left the silk washer whole. The silk seller’s motivation out of poverty was noted, solved by the traveler and not unfairly so he was “bought” and cooperated fully with what was a great deal for him, which lubricates away resentment, half effort, and unhappiness because giving a good deal to someone is sim…
The silk washer has no ability to even make use of the knowledge that the ointment has other potential applications or that it could be very valuable. It seems like a distracting element of the story.
If the dynamic of "don't try to rip people off when you have an informational advantage" was the point, it should have shown a consequence for doing so. As it stands, I see no reason why he shouldn't have offered 1 cattie of gold instead of 100.
Normal western storytelling would either
* Show the consequences of an action
* Have the character recall specific advice on the right thing to do; or reason through it; and then benefit
In this case a choice was made and it was fine-ish. But given we don't know how wealthy the traveler was, we're left to wonder if he was either:
* banking his entire net worth on this ointment
* saying "it's one ointment, silk guy. What could it cost, 100 catties of gold?" with a certain opulent flair.