Apple has very strict controls around what apps can do on an iPhone or iPad. It simply isn't possible to release an app to the App Store that creates entries for these 'native' apps. Only contacts and calendar entries can be created directly from within an app.
MyBB allows the other kinds of data from a backup file to be viewed so that you have it available to refer to. The information shown can also be copy/pasted over to another App (touch and hold an item such as a memo to see the copy/paste menu).