systems architecture is used to make a system with a large work or a somewhat more complicated. If the software is not very complicated, so do not need the systems architecture of the system. Systems architecture is capable of making software, knowledge of the hardware, and the use of different languages in programming.
In my opinion, the systems architecture of a lot to do, but the system is large and complex. Need a good team and are competent enough. In a large system, and also requires discipline and punctuality to work.