One need to handle security differently for mobile devices and for laptops. When it comes to the example I gave above in one case a person can read the contents of the files, in another case the same person can copy your entire content. Now if that's not something to worry about, what is!

That's not worrying at all. Considering you need the passcode of the device to do so. If they have the passcode, or there isn't one, then the attacker can just open the app and look without extracting the files. These aren't passwords stored in plaintext. This is plaintext stored in plaintext.