I assume you're thinking about translation flashcards when you say that manual input should not be used, but I get a lot of value out of dictation flashcards in Anki: the front plays a recording of a sentence, I type in what I heard, and I mark myself correct if I wrote the right sentence and understood its meaning.

With translation, the problem is that there's often many correct answers, which makes it difficult to distinguish wrong answers from unexpected correct answers. But sentence dictation usually doesn't have this problem (barring puns with homophones.)