When you’re at the checkout and the cashier asks for your phone number to apply loyalty club discounts, it takes a little extra time. A small thing, but the cashier is already holding a barcode scanner, and it can read your number with a simple beep.
I’ve previously made both a paid and a free app for Android, but many people have iPhones, and many might not want to install a separate app. Don’t despair, because I have created SnartCard as a web application.