In the beginnings people used to pay each other in gold or silver. Gold and silver were quite heavy and inadequate to manipulate with. Then, society came to a new age – people started printing paper money. Regular currencies are based in gold. They are literally like bonds that have value in gold reserves. Paper money became much simpler you could divide it without any difficulties and you could use it everywhere.
Since banks started printing more money than they had gold to begin with central monetary system was invented. Central banks started to guarantee for other banks. Central banks were managed by governments, although they have some sort of independency. Still in the 70s gold ceased to be the guarantee of the paper money. So, governments could print as much money as they want. To justify this creation of value without any background to it, prices kept raising every year, although the evolution of technology should have made prices go down. With regular money nothing changed, gold and silver are still hard to use.
Basically, society needed an alternative to the regular financial system through which people could trade. When Satoshi Nakamoto invented Bitcoin peer-to-peer transaction system, society got the best alternative yet. Now, everyone can try his luck with day-trading, mining, etc. Important part is that today we have stabile digital currency that is used all over the world for transactions of all sorts. Most of the online traders use Bitcoin nowadays and even some of the biggest networks included Bitcoin as a valid method of payment, such as Microsoft, Amazon, etc.
Bitcoin is independent from any central bank or any sort of manipulation by any government on the planet. People who use and create Bitcoin are those who are in charge of its future. That is the most important purpose of Bitcoin. Most of the early adopters of Bitcoin were libertarians and innovators, but today bigger part of the global society is starting to use Bitcoin. Now, people have an alternative. They can store value or trade with it without any control of the elite parts of the global society.