Lidl Smart-Tarif and German bank account

[matt]

Hello,

I will be doing an internship in Berlin for three months and I am looking for some information about prepaid SIM cards.
After searching a bit this very useful forum and Google I think I now have a general overview of the different offers and carriers, however there is something which is not clear to me yet and I hope somebody here can help me in this.
I was considering Lidl Mobile since it's cheap and it uses O2 network (and there are stores near where I'll be staying).
I understood that I won't need a German bank account in order to activate a SIM with the "Classic-Tarif", however I was really interested in the "Smart-Tarif" instead, since I would like to use internet on my smartphone pretty often and have a certain number of minutes/messages included.
What isn't clear to me is whether I need a German bank account to activate the Smart-Tarif. If yes, is there any other way to activate, maybe using a credit card? Or are there plans from different operators at more or less the same prices as Lidl but that don't require a bank account?

Also, when you buy the Starterpaket at a Lidl store, is it possible to choose between a SIM and a MicroSIM or they only sell standard SIM cards?

Thank you very much in advance!