Here's the real scary thing:
She's making a choice to not threaten the magicians with the crystals. That can only mean three things:
1-She wants to facilitate good relations with the magicians, such as trade (magicians lack interest in politics, power struggles, and money. They're basically scientists, and would avoid war if possible), implying she's VERY confident of creating, stabilizing, and maintaining a win-win situation, which implies she knows thoroughly she has the advantage.
2-She's confident of winning a war against magicians. Her position implies with mana crystals that all humans, elves, and dwarves covet, that she can easily convince an entire race to give military aid to her. AN ENTIRE RACE.
3-She's planning to cash in the threat for something of even higher value. Examples could include: threatening all magicians to be pacified/subordinate under her after she gets elves or dwarves to ally with the Lachia Duchy, or straight up planning to murder every magician in existence.
All of this assumes she's aware of how powerfully important the mana crystals are. The Lachia Duchy could be the centerpoint of an interracial war. Her previous competence "proves" she obviously can recognize it, and the fact that she has chosen option 1 implies she's confident she can manipulate magicians, dwarfkind, elvenkind, and non-magician-humankind all at the same time, AND chose to facilitate trade instead of wage war. Implying she wants to take economic victory.
The Lachia Duchy is about to be the new capital of an economic empire. She's well in a position to forge an empire without even needing to fight any wars.