Tracks, ramps, and a German midget submarine

Why did the German midget submarine have tracks, and were they intended for climbing over reefs?

The tentatively recalled purpose was to use launch ramps, reach maintenance buildings, and move between waterways over land.

The small German submarine combined torpedoes with a tracked undercarriage and is remembered as prone to falling over. The suggested explanation for the tracks is that the craft could use launch ramps, reach warehouses for maintenance, and move over land between canals or channels. That purpose is recalled with uncertainty. A simpler alternative proposed is a wheeled carriage onto which the submarine could float before being towed away. The question is whether making the submarine itself move over land justified the extra machinery and stability problems.