The initial reason was relatively simple, that is, it was disappointing to rescue Italy. Stop Britain from occupying Italian colonies in North Africa. Italy, even the Balkans and Europe (Churchill's famous words) are directly exposed to the threat of Britain.

Later, Rommel played more smoothly, and Germany's attempts and ambitions further expanded. Trying to capture Egypt and cut off the Suez Canal not only forced Britain to bypass the Cape of Good Hope and keep in touch with India and the Far East. At the same time, based in Egypt, it can enter West Asia and the Middle East, instigate anti-Semitic and pro-German Arab countries and Persia to turn to Axis countries, induce Turkey to participate in the war, threaten India, cooperate with Japan, and open up a battlefield against southern Soviet Union.

To sum up, Germany is far from occupying Africa at present, and it is basically confined to North Africa.