You need to also consider labor cost of installing that cable and switch. That's usually more than the cost of the materials.
These wireless switches need relays to work, so factor that in. And then factor in the time it takes your $120/hr electrician to figure out how the wireless switches work.
I would use a $30 Lutron Pico with a button cell and RF communication over this silly device that generates its own power.
But what do I know, I only sell electrical services for a living.