No one knows who Satoshi Nakamoto is. But he, she, or a collective had a vision for a new currency in 2008. This gave rise to Bitcoin — a fundamentally new method for storing and transferring value. In contrast to conventional financial networks, Bitcoin does not require central authorities or trusted third parties.
In addition, there is only a limited number of bitcoin, which means that it retains its value similar to gold, for example.
Over the last 10 years, the price of a bitcoin has risen sharply. However, you don't have to buy a whole bitcoin, because 1 bitcoin can be divided into 100,000,000 sats. So you can also easily buy bitcoin for just €15 for example.