I don't understand the purpose of this method of unlocking a Jade wallet. When I select the QR mode in my Jade, it prompts me to enter my previously selected PIN (6 digit number) to the Jade. Then the Jade gives a QR code which I need to scan from the phone (or PC with camera). Then the web page shows another QR, which I need to scan it using the Jade. Then the Jade issues QR, which I need to scan with the phone. Then the web page issues another QR which I need to scan with the Jade.

How does this scanning QR back and forth between the Blockstream website and the Jade wallet adds any security? Once the PIN is entered, anyone can do the same thing. How is this method any more secure than just entering PIN to unlock a wallet?