Privacy

Why are you being so condescending?

Phones get lost, stolen, damaged beyond repair. I knew a woman whose phone fell into a body of water on vacation and couldn't be recovered.

When you have an app used by millions of people, which they depend on for tracking wellness, health issues, reproductive planning, etc. it makes sense to have a cloud backup for those inevitable situations.

Also yes, not everyone knows how to initiate an NFC file transfer, or even how to navigate their phone's file system to select the data to transfer. You often have to develop software to the lowest common denominator. There's open source options like Mensinator for people who want more control and privacy, but most software on the app store is targeted at less technical people.