Tunis offers greater port capacity while Libya remains exposed

Would Tunis offer the Italians more port capacity than Tripoli?

Yes, but capturing it could leave Libya vulnerable to a British advance behind the Italian forces.

Tunis has greater cargo-handling capacity than Tripoli, whose limited throughput constrains Italian supply. Capturing it would therefore offer a logistical advantage in this counterfactual campaign. An Italian advance into Tunisia would nevertheless leave Libya exposed to the British. The larger port could be gained at the cost of losing territory behind the advancing army.