There are people who loves to collect different things, I have learned that there are people who collect earrings, shoes, pillows, guitars, and even paper bills and coins.
My mom has her own collections of old and new coins too, though it is not much, it is enough to be called a collection. She used to buy silver coins from different sellers and now she stopped, maybe because she has no time for her hobby anymore or maybe because she has find another one.
But there are people who devoted their time finding the most unique addition to their collection. Searching the world for every old coin they can find in antique stores. I think coin collection is a hobby for the people who can afford to buy them, as for me, I am contented collecting stamps and postcards because it is much cheaper.