You do that in an indirect manner, by requiring NFC, thus eliminating 4-inch phones, which don't have NFC: https://developer.apple.com/library/archive/documentation/De... (Cmd-F nfc). If Apple had updated the iPhone SE with NFC, this trick wouldn't work any more, and I'd be forced to do UX design for 4-inch phones.
Till I find product-market fit, I don't want to be distracted by overhead like this.