Fewer emails asking "where do we stand"
The client logs into their own view and checks for themselves what is in progress, what is waiting and what has been done. They submit a new request where they see the previous ones, so nothing gets lost in an email thread with four people in copy.
They see their own matter, not your workshop
The portal is a separate context, not the same screen with hidden columns. The internal note on a task, the team's rates, other clients' matters - all of that stays on the agency side. Permissions are enforced by the same mechanism that separates roles in the team.