When the package is actually delivered, the
    customer receives an email notification along with
    a bar code to his smartphone and heads to the
    7-Eleven. There he’ll stand in front of the
    locker system, which looks like the offspring
    between an ATM machine and a safety deposit box.
    The machine will scan the bar code on his handset
    to receive a PIN number. He’ll punch that PIN
    number and retrieve the package.

I don't understand the purpose of the PIN. If I'm reading this right, it scans the bar code on my phone and gives me the PIN, and then I enter the PIN to get my package.

Why doesn't it just give me my package when it scans the bar code? The PIN doesn't seem to add any security.

I supposed the PIN could be an artifact of the implementation, rather than a security measure. For the prototype it might have been easier and cheaper just to use some stock keypad-based lockbox, and so they have to tell you the PIN, rather than to do some custom engineering to hook the locking system straight up to the barcode system.