I think if this product, as advertised, interests you in the slightest you should reserve one for the $5. There is no good argument not to unless you genuinely know you have no interest in the overall concept of this.

Okay, so where do you draw the line though? Imagine 20 similar products announced on the market, and they all slightly interest you. Do you reserve one of each for 5 dollars? By your logic there is no good argument not to.

And why does valve deserve the money? Steam has 120 million monthly active users, I'm assuming they're all slightly interested in new PC hardware. Why does steam deserve 600 million dollars in reservations?