Her ability sort of grow stronger without going through the evolution. Later on she can 'jump' with the line for instant movement.
And Roland admitted that given how incomprehensible Nightingale's ability is, he can't help her in this regard.
She's still one of the most valuable witch for Roland though, even without talking about combat:
1. She can see magic power, meaning she can easily detect witches.
2. She can detect truth/lies, so she makes interrogation a breeze.
3. Her invisibility makes stalking targets very easy (or staying next to Roland when he's 'questioning' someone)
She eventually become the head of security bureau when Roland establish the police.
He will help Mystery Moon get a 'shortcut' to her evolution, but evolution through this sort of snap enlighten moment is weaker than Anna's type of full comprehending the knowledge.