We've been continuously selling the practice angle with DS.
Personally I found it insulting as child to be told to try harder to do something I was already trying twice as hard at as the next kid. Specifically regarding handwriting where trying even harder meant increased hand pain. On the same token, I hated being an example in math where other kids were told to work hard like me, when it was at base a complete lie. The only effort in grade level math was the handwriting component.
Might also consider that the scribbling is an ego cover where she is acutely aware of how far apart her best effort is from what she would like it to be... self-recrimination may be less healthy than scribbling.
