flashcards for learning Chinese. And perhaps the advice I should give you is: Use it if it works for you, and don't use it if it doesn't work for you.
But I should also state that I have benefited so massively from the use of flashcards, that I really believe you should use it - regardless of whether you think it might be useful or not.
Just do it.
My use of flashcards has evolved over the years, and that's probably why I'm still getting value out of them, starting with individual words (excluding Chinese characters), progressing through to much more complex sentences which include the hanzi.
I use Anki, which is an SRS (spaced repetition system) program that runs on most operating systems. It's incredibly intuitive, very flexible, and free. You may as well install it now, if you haven't already done so, and you can learn more about how to use it optimally in the next few posts I write.
One of the more common arguments against using flashcards is that if you are reading books & newspapers & websites in Chinese, then you will end up learning the most common words anyway, without wasting your time on words that you might almost never see.
But most students of Chinese are not at that level, and therefore most students really should be focusing on accumulating words as quickly as possible. The more words you know, the more you will understand and the more you will be able to say. A flashcard system is, in my opinion, the best way to get there.
So if you're an advanced student, flashcards might not be for you. But for anyone else ... Just do it.