Better scanning in low light, better error correction in code recognition, ability to recognise codes from a further distance, faster capture of codes, more options of what to do with the resulting data, reduced power usage while scanning, better user interface choices (e.g. updating to support more devices or matching new platform UI), ability to interface with external barcode scanners, better privacy protections for the user, reduction in overall package size, etc etc etc.

There’s always more things you can do to a product to improve it for its users.