Unicode is one of those things people don't commonly think about, but benefit from immensely. To explain why Unicode was necessary, we need to look back at the early days of computing.
Before the 80s, if you owned a IBM mainframe, you were pretty much stuck only buying IBM computers. The reason for this is that IBM computers could only talk to other IBM computers, due to there being no "standard" way to encode characters. This meant that even files made on an IBM likely couldn't be read by competitor's machines.