There is at the end. The end of the article in its entirety are objective reasons.

1. Necessity to operate on the fringes of financial system.

2. Better ability to maneuver with regards to moving, transfering, liquidating positions to make redemptions.

3. But most importantly as has been learned by the centuries of banking and the like, opacity, especially where it is ignored because understanding it is hard is helpful to solidify shaky concepts (FRB).