There are a couple of reasons why we didn’t use this approach.
Log in to the web here is by using just one factor, and it is not in line with the circular released by the exchanges.
There are chances where phishing websites can be set up where the QR code can be mimicked, resulting in a security issue for the client.
Password and PIN are both knowledge factors, and the circular specifically mandates that a possession factor be used as a second factor; hence, we won’t be able to use this approach.
The number of folks who will use this would be very low currently, but we will explore this.
Also, someone has posted a solution for multiple accounts here. The same approach can help for managing single account as well. Check if this post helps.