Comment by kbenson

Importantly, I think it's much more obvious what you're doing with a web app when you upload data. There's an erroneous belief when you're using native app that the data you provide to it never leaves the device. That might be the case, but even in cases where the native app isn't just a shim to do something through a service, there's little guarantee they aren't utilizing your data for their own purposes, legally (e.g. Adobe) or not.

This isn't unique to mobile vs desktop, but from my experience people use those different device types with different levels of care. It's possible app stores play into this by giving people an incorrect sense of security about aspects of application usage and updating that they don't actually provide.