Moshe was commanded to count the working force of the nation, and each tribe was assigned their exclusive place in the camp and in the travel line-up. The transition from the desert to the Land would be traumatic, and the Bnai Yisroel needed to be prepared. Therefore, the key features of these two and Parshios is transitionary aids and strategies. Whether the census, the individual placements of the tribes, or the selection of Shevet Layvie, the focus is securing the nations relationship with G-d in the aftermath of the desert experience. Therefore, G-d decided to have a parade.
Parades serve many different functions.
In many instances, such as most of our parades, they are forms of entertainment. Everyone loves a parade. In other situations, they are intended to engender awe, respect, trust, confidence, and a sense of security. At other times, a parade allows the general public to show their appreciation for their heroes, or to commemorate past events and achievements. In order to accomplish the intended theme of a parade, great attention must be given to the organization and presentation of the participants.