The keyboard could easily switch between upper and lower case depending on what the user is actually entering. Why wouldn't they do that? It just seems like an easy win.
Dunno about myko, but every time I use an iOS device it really confuses me. Comparing it to a physical keyboard isn't fair, since on software keyboards shift is stateful. lower/UPPER casing the keyboard is a much larger (very convenient) indicator of that state than the altered shift button.
