Why is TurboTax download cost $20 more than CD from BestBuy?

I find these prices for TurboTax Deluxe 2018:

 

Download from Intuit:               69.99 USD

Buy CD at BestBuy store:          49.99 USD

 

Why is the price of the CD and box apparently negative 20 dollars?  Do I need to scrounge up an old computer with a CD ROM drive in order to save 20 dollars?