Two reasons: 1) It's a slick PR move and a gesture of goodwill to provide instructions for how to unbrick the device 2) For a $30 product, the cost of shipping

Two reasons: 1) It's a slick PR move and a gesture of goodwill to provide instructions for how to unbrick the device 2) For a $30 product, the cost of shipping a unit back would be approximately equal to the BOM so it's almost as cheap to just throw it away.