The benefit of their process is seen in the final product. There is no need for gauges to check for headspace or special fitting. Tolerances and quality control are held to such rigorous standards, any STG-556 part will work in another STG-556.
The Steyr AUG was designed as a family of rifles that could be quickly adapted to meet a variety of situations with a quick change of the barrel. The STG-556 maintains this modular design allowing the user to quickly configure a carbine with optional Picatinny rail attachments that is capable of securing the availably array of lasers and optics.