CREATE has a simple SHARE option which gives an individual URL / easy to make hyperlink to the specific sketch.
I can see QR as being easier to implement and use into CREATE where there is already a secure environment.
But as for online you would need to have REPO's set up properly in secure domains.
QR codes can be misused too.
What would be to stop somebody saying it was a sketch for BLINK and swapping it for a virus link.
Just my 2cents.