One thing to note is: I can't find any mention of returns/refunds on the wurkkos website, while Amazon has their standard (very liberal) return policy.

From the manufacturer's standpoint, they pay 15% referal fee to Amazon for getting them the sale. They also have a 5% coupon. Taking both of those things into account, their revenue on the sale is ~$64 compared to the ~$54 on their site. But I'd wager they're not getting very many sales on their website.