#4 To keep her out of the title picture, even when she recovers
Alexa Bliss has been one of the most prolific characters in the women's division. She won the Elimination Chamber match as well as the Money in the Bank ladder match, this year. She even went into WrestleMania 34 as RAW Women's Champion. And yet, there's no place for her in the current Championship picture.
With Ronda Rousey capturing the Championship, the RAW Women's Division has a different feel. Rousey vs. Bliss has already transpired and Rousey absolutely obliterated Bliss on that occasion. Fans will probably not want to see a repeat of what was essentially, just a squash match.
By having Bliss as an authority figure, it allows her to be on TV but removes her from the title picture. This point is actually a lot more applicable for when she eventually returns to action.