I dunno. I guess Watch City Slices is so good nobody wants to trade away any of it.
There are only 9 reviews at TR.com, but 7 are 4-star, and 2 are 3-star rated. So, not widely known, but apparently well received. If my experience with their Old Dominion and 558 is anything to go by, what they call slices are probably crumble cake, and not something you can slip into an envelope like thin flakes.
This is on my bucket list too.
But to the OP, why not just order 2 oz.? The postage is an issue you'd have to deal with even in a trade situation.