Bitcoin was developed as the worldwide payment system, so it can be used anywhere. It has tried to stand as the currency of the world. So the question arises here, as we already have paper currency why would we need a digital currency like bitcoin?
Bitcoin is not regulated by any government so while performing transactions, people do not need to have middleman like a bank for performing transactions, so it saves money and no need to pay taxes for sending money to other countries. People will have their own control over their money and blockchain technology is safest and unhackable.
Bitcoin is only available up to 21 Million bitcoins, then after that, it will not get produced anymore. The production will cease by 2140 as of now the supply is just 16,931,163. It has also gained its value due to more people using it. The popularity gains also increase its value because of limited resources.