QR code sign-in places a printed QR code at the open house so a visitor can point their phone camera at it and open the sign-in on their own device, with no app to install. It moves capture off a single shared tablet and onto every visitor’s phone at once.
That clears the line during a rush and lets a visitor register straight from the sign rider before they even walk in. The code just needs to point at a sign-in page that works reliably, including when the venue has weak signal.