Why are Kingdom Halls sometimes built in the "quick-build" manner?

Wikipedia has an article on Kingdom Halls that states: > In many countries, a number of standard designs of construction are used that can be built in just a few days. The act of constructing a Kingdom Hall in this manner is called a quick-build, although typically the preparation work involving the structural foundation and surrounding surface may take several weeks prior to the scheduled build. For various reasons, not all Kingdom Halls are constructed as quick-builds or using the standard designs. Seeing many issues that can go wrong with building something so quickly I figure there is some sort of theological importance in doing this, however, not all are *quick-builds*, so it cannot be all that important. Why do Jehovah's Witnesses build their Kingdom Halls in three days? Please provide quotes and links to official sources