Taking a child who's set on acting to auditions is never a waste of time. You're suggesting her - and your - time was wasted because she didn't get the role.
Autioning's a much a skill as dancing, singing and acting, and practice is essential.
Acting's not about who you know - it's about who knows you. And getting known, seen and heard out and about is the way to get known.
And remembered. As reliable, good to work with, supportive parents, hard working, team player, taking direction and feedback well, as well as being good at it.
She may not have been cast this time - but as casting directors see her, she'll start to be remembered.
Building a pro reputation is about hard slog, determination, rejection, pick yourself up, dust yourself down, have another go. And that can start in childhood.
So she didn't get this one. Let it go. Help her to let it go. Next.