I find being able to report right/wrong answers makes flashcard programs much more effective. Once you try a program like Mnemosyne or SuperMemo, you'll never go back to paper flashcards.

http://www.supermemo.com/english/ol/sm2.htm

or anki, the OSS version of supermemo:

http://ankisrs.net/

or Quizlet.com :)

Tapping the screen eliminates the benefit of using the cover alone as input and makes handheld use of this app even more difficult.

One might not be able to keep score easily with paper flashcards, but that doesn't mean it's not useful. I'm not that familiar with handheld flash card app space, but I could see an app providing score tracking and more frequent interweaving of previously missed answers, and an overview of immediate feedback can be helpful.

If theres no advantage over paper flashcards then why use such an expensive device instead of $1 paper?

Statistics are pretty much the only advantage I can see for using an iPad here instead of physical notecards, unless you have so many notecards that it would be a pain to carry them around which seems like a very obscure use case to me.

> I don't have a way to do it with paper flashcards ...

Most people separate paper flashcards into two piles as they go, one for those they got right and one for those they got wrong.

1. Tapping the screen means you're using 2 hands.

2. If you aren't using spaced repetition statistics with your flash cards... you're doing it wrong.