Dialog in a board game

I've been fiddling around with a idea for a while now for a card driven dialog engine for a tabletop game. I see it mostly as a quest generation and merchant interaction mechanism. I'm sure it has other uses as well.

The basic procedure of the system is as follows:

1. The active player chooses to do something that engages an NPC
2. Another player draws a card from an NPC deck holds it so that the "Front" faces the engaging player and reads aloud from the "Back" of the card.
3. The engaging player would then choose a card from their own selection that had matching symbols, hold it so that the "Back" faces the player reading for the NPC and read aloud the section that matches.
4. The NPC player would then read the result that matches the symbol on the back of the card the engaging player read and carry out any instruction text.

In the above example, it would play out something like this:

1. Engaging Player goes to the Merchant. The player to his left draws a card from the Merchant Deck.
2. Merchant - "Friend! You'll never guess what I just came in! And i'm offering it exclusively to you. According to Legend this sword was forged by Volcan himself for Herecles. What do you say, I'm only asking 100 gold?"
3. Engaging Player selects one of their cards and reads "Seems like a fair exchange. I’ll take it."
4. The NPC player looks at the card the Engaging player choose and reads "A pleasure doing business with you." and gives the player the Sword of Herecles. The engaging player spends 100 gold.

So... any thoughts? Does this sound fun or just cumbersome?