Why is this a craft? Doesn't it have more in common with coinage, astronomy (navigation) and mathematics (beancounting) - i.e. it is a science - than cloth making, pottery and mining? Trading is the "art" of planning how and when to sell and buy stuff, not the actual making of it (as crafts is), in my opinion.

The only reason for this being a craft would be to balance the number of advances in each group...

Hmmm.. I always considered trade to be part of the Crafts section. I'm not sure why... other than its more like applied science rather than the more abstract stuff.

I've always seen Trade Routes as the actual discovery and utilization of the actual ROUTES as in "The Silk Road" and the need for crafts to maintain (roadbuilding) and use (crafts to trade). I don't look at it as an economic study.