The countries of the world are divided into unitary and federal countries. In unitary countries the central government is in charge of all of the matters relating to the country. It can devolve power to the lower tiers of government but can at will take that power away. In federal countries the central government represents the country to the outside world but otherwise the country is divided into regions which all have their own governments and laws. Of course, there are great variotions in this point. It has been said that a Canadian province has far more say in its own matters than a US state.
Austria is a federal country. Why is Austria a federal country? In my opinion federalism is needed when certain circumstances apply. That is a) If a country is geographically very large b) If a country is very populous c) If a country is made up of many religious factions which just can't stand each other d) If a country is made up of many ethnic groups which just can't stand each other.
None of this criteria applies to Austria. Canada and Australia are federal countries because they are so huge in size. Belgium is a federal country because it is made up of two different communities which don't really like each other.
Even Japan is a unitary country though it is very populous and relatively large in terms of geographic area. Germany could as well be a unitary country but the Allied powers wrote the German constitution to make it impossible for the German central government to have too much power. Very understandable.
But why on earth is Austria a federal country?