Because unlike other smartphone rates, which advertise with monthly data volume contingents, Aldi Süd hides the hook here in print. 12 GBytes covers the entire duration of the tariff. That means you have 12 GB for all 365 days. If you surf excessively in the first month, many things will disappear in the following months.
However, small surfers must be happy with the offer. Because basically Aldi Süd offers rates here around five euros per month, which can also be paid in full for a year in advance. In a package with the Samsung Galaxy A10, an annual package for 159 euros starting November 21, 2019 is offered.