What makes Collectors fall in love with Indian Notes?

Money is what rules the world. If there was no money how would civilizations evolve? This power of money is what makes many collectors fall in love with currency notes. I have some friends who are into collecting Indian Notes. I always wondered what makes them want to pursue such a unique hobby. The most common hobbies that you would hear about is listening to music, playing a sport maybe. But this unusual hobby of collecting currency notes in India made me curious. 

Finally I went up to them and asked them why they are collecting Indian stamps. One of them answered saying that he loved history and by collecting Indian notes, he kind of stays connected with his field of interest. Thesn I questioned him further to find out what kind of Indian notes he likes to collect. He told me that he keeps looking out for currency notes in India that were issued when our country was colonised by the Portuguese, French and the British. I got a change to look at his amazing collection of Indian notes and was spell bound literally. I suddenly realised why he likes his hobby so much. I gazed at those lovely currency notes in India for almost an hour. Each note had a story to say. For the first time in my life I saw one-sided Indian notes. They had designs and inscriptions only on one side. 

Then I went up to another collector, he was different from my earlier friend. He liked collecting currency notes in India with fancy numbers on the serial number. For example, all ones or all twos. He had a certain terminology for each of these notes. The Indian notes he had with a serial number having the same digit were called super solid notes.

On that day I discovered that it is not really strange for someone to fall in love with the hobby of collecting banknotes!