The reason is stablishing two facts: that he wouldn't have sold if not for SR and that the buyers wouldn't have bought if not for SR. Also in he article you'll

The reason is stablishing two facts: that he wouldn't have sold if not for SR and that the buyers wouldn't have bought if not for SR. Also in he article you'll find why: it's a rebuttal to some defense's argument. I would have asked the witness the source of the $3,500 before he had access to Silk Road. But it doesn't seem just an arbitrary emotional trick.