They aren't! You would have to be investing BTC into SOMETHING ELSE. That's like saying trading USD for Yen is part of the GDP. If anything BTC would count as part of the US economy as an asset being invested into.
^^ He is on the right track of thinking but not fully understanding it.
I honestly do not know what you are trying to argue. The numbers don't lie.
Silk Road (past 30 days): 30000
BTC.
Bitcoin network, minus change (actual transaction volume):
8979180 BTC.
It doesn't matter what you consider as part of the Bitcoin economy. Silk Road is, and will always be, an insignificant part of it.
What do you believe the number is for total consumer spending in the BTC economy? That is what will get bitcoin higher. not hoarding and trading of the commodity itself. Spending it in exchange for another good or service. right now, vice is too much of that.