The cruisers were carrying fuel and supplies quickly toward ports close to the North African front. A complete blockade of North Africa was impractical. Allied interdiction could still prevent cargo from reaching the most useful port at the critical time, forcing supplies into distant dumps that became useful only after Axis forces withdrew toward them. British coastal convoys offer a parallel: they redistributed Atlantic cargo after it reached major ports because road and rail alone could not move everything efficiently.
Notable Point · 1:03:13-1:06:14
Why the destination of supplies mattered
The Cape Bon mission illustrates that interdiction could matter by forcing cargo into distant ports, even when the Allies could not stop every shipment from reaching North Africa.