Closed Workspace for Pro Account

I don’t understand why having a closed workspace isn’t available for pro accounts. $16/seat/month doesn’t get me this simple feature? I have to inquire about an enterprise plan for this feature? I don’t get it.

Once joining, they have access to all Main boards within that workspace, and any Private/Shareable boards they’ve been invited to. Any team member subscribed to a board from a closed workspace will have access to that board but will not be able to see anything else within the workspace.

Thanks, but I’m not talking about boards, I’m talking about workspaces.