Earlier this year implemented saving event tickets to Apple Wallet (and Google Wallet, which was painful by comparison!), as an optional alternative to recipients leaving the QR Codes in email or printing them.
Scanning barcodes on entry is done using camera on phones (either iPhone or Android). This is a somewhat pressured situation with lots of people needing scans in quite a short period of time. I do not do this myself but I do get feedback.
it was reported to me that Apple Wallet barcodes are significantly harder to scan accurately than those in Google Wallet. They think that is because the Apple QR Codes are quite a bit smaller (and presumably harder, therefore, to get focussed properly). They do work, it just takes longer to get a successful scan. This doesn’t seem to be anything I can control, and there seems to be plenty of space to make them bigger, even on my iPhone mini. These aren’t terribly dense barcodes; I imagine they would be harder still if they were. I also guess specialised barcode readers might do better, but we don’t have that luxury.
I’d appreciate it if they could be bigger when displayed in Apple Wallet, or at least to have that as an option.