Yes. Even though the regulations may have been more flexible as of late, it is necessary to do the program in Berlin. A structured program is different from the individual PhD or a part-time PhD - GEAS offers a full-time course and work program for researchers who aim to finish their PhD within 4 years. Most scholarships are also only granted for the purpose of full-time study in Germany, and some are only available for FU students who reside in Berlin.