Stepping back from socio-political arguments a moment... What is really fascinating was that Germany didn't exist prior to unification in 1871. What is now Germany was a series of individual kingdoms, dukedoms, city states and princedoms. Back in 1914 I guess that to a lot of older people, calling them "German" would have been as much an insult as calling a Canadian, "American". Each of the "princely states" as they are referred to in the catalogues have their own monetary systems and weights and measures. Germany was only 43 years old at the outbreak of WW1.
In case people are wondering I am a numismatist (a coin collector for the benefit of FVW). I have several coins of pre-unification, including a Prussian victory thaler for the Franco-Prussian war.