The roots of course can be found in the Bauhaus tradition of a New Vision of reality. The M3 is just the perfect instrument for the art of the snapshot, the poetic registration of fleeting moments in a days life of urban and human experience. The M3 does not interrupt the stream of consciousness in the mind when experiencing and visualizing the focus of interest. They tried to create a distinct artform with its own rules of the game. Salgado, Cartier-Bresson, Seymour, Boubat, Doisneau and many others played according to the rules.
Form follows function.
A modern SLR with motordrive and zoomlens is bigger and heavier than a medium format camera which boasts a much larger picture area. Here the efficiency and functionality relations are gone. The M3 is a much better design as it exploits the smallness of the 35mm format into a highly functional and efficient body. Small format photography is different from a photography based on the 35mm perforated film. The M3 reigned when Life and others dominated the communication market.