Eunuch's historically have been used by powerful Muslim rulers for administrative purposes.
Mohammad El Arian is precisely the bureaucratic eunuch needed by both Trump and his Saudi ally, Mohammad bin Salman.
Finger on the Trigger
With El Arian as a Fed Vice Chairman, Trump can better position his Team to blackmail the wealth of anyone in the anti-MBS opposition.
Trump Opposition: Militantly Against MBS
MBS' coup was considered a disaster for the KSA by the Trump opposition: it not only provides Team Trump with unlimited financial backing, but it forestall their control of a critical region and can ossify political and strategic outcomes that violate or frustrate their own strategic agenda.
Team Trump is not wasting its time with a "peace deal": it shoots straight for the jugular, crippling the power of the opposition to secure its hegemony for generations to come.
Mohammad El Arian is a sign of anxiety and weakness, not strength, of Team Trump: it clearly must be prepared to "destroy the village to save it".