Splitting the work means every recommendation has a named author and a reviewer who can veto it. You only ever talk to Vera — she pulls in whoever she needs.
A single model asked to research, trade and manage risk in one pass has no one checking it. Splitting the job means every proposal is written by one agent and reviewed by another before it reaches you — and before that, it has to clear limits that are enforced in ordinary code rather than asked for in a prompt.
Roan is the one that says no. Every proposal from Sage or Cleo goes past him, and anything he amends or vetoes is recorded with the reason. You can read that record for any decision.