Why Malta would have been difficult to invade

Would Malta have been difficult to invade, and why did it matter so much?

Yes. Its terrain and urban fighting would be difficult, while its capture could have materially improved Axis logistics in North Africa.

Malta would likely have been harder to invade than Crete. Fighting through Valletta and the island's prepared positions would impose a demanding amphibious and urban battle. The difficulty did not reduce the strategic attraction of the objective. Control of Malta could have improved Axis prospects in North Africa by easing pressure on their sea supply lines.