Because what it brings is an increase in "priority."
The Transcendents of this world use "Energy Level" to summarize their ranks because in a clash of abilities, a Transcendent with a higher Energy Level is more likely to make a successful determination. When Energy Levels are the same, the outcome is less certain.
For instance, the Path of Authority possesses a Law Magic called "Omnipresence Incantation," which can reveal things hidden by transcendent powers within a range. This spell has a +1 advantage (reveal), meaning it can be successfully activated even if it is one Energy Level lower than the opponent's, but if two levels lower, it essentially can't detect anything.
Therefore, those low-level Inspectors and Legal Mages cannot catch Miss Assassin— their levels are too low, and no matter what they do, they cannot find where she is hiding.
