To answer the question, "why would I use this instead of the [Tenet Grigori] which is definitely better?"
The answer is, flavor.
[Condition Overload] and [Primed Fury] replace [Gladiator Might] and [Sacrificial Pressure] (from the Grigori build). This should give the [Tenet Livia] a greater force and handling, and makes status priming important. The attack speed is doubly important to make use of light attacks to build combo when ideal.
The innate Magnetic shouldn't matter, but it's nice to have something different.