Bitcoin is a digital store of value.
There are markets and exchanges in the world where Bitcoin could be traded with fiat currencies such as the US Dollar (USD) or the EURO.
What makes Bitcoin special is that it could be digitally transferred between people anywhere in the world. This makes Bitcoin a global currency, and it takes the same amount of time to send Bitcoin to your next door neighbor as it takes to send it to China.
On top of this, Bitcoin is decentralized. This means there is no key governing authority for Bitcoin. Unlike Visa Card or Western Union transactions, Bitcoin does not have any single entity that governs it. Central authorities are a point of weakness as they have so much power they can be used against the interests of its users.
For example, banks commonly lend peoples’ deposits to other banks etc. However there have been cases where banks have failed to repay their creditors and collapsed. And whilst some governments offer deposit protections, there is a limit on this amount and depositors will have no way of getting their money back.
Bitcoin solves this problem because with decentralisation no one, including the banks or the government can take your bitcoin.