[em500]

> Practically, many people however only start thinking about possibly needing to open some app to display it while they’re already blocking everybody else’s way at the transit gate…

This really comes down to adoption. In China, where QR is ubiquitous, almost everyone has the QR ready to scan well before they reach the scanner.

[tonyhart7]

if its work on country that has billions of passenger, it would works on everywhere else

[lxgr]

Not necessarily. Regular riders vs. infrequent riders or tourists can make a big difference, for example.