simple answer is supply and demand people trusted it people pay it and make the bitcoin is worth
Exactly! Without bitcoin limited supply and higher demand, it will not worth too much. That's why bitcoin is the king of all cryptocurrency because of a lot of people believe on it.
As long as there are people who trust Bitcoin and use it, it means that the demand is always there, then Bitcoin will not die and it is impossible for
its price to be zero. That's the reason why until now Bitcoin is very strong and the price continues to rise, even though many big countries are trying
to kill Bitcoin. But Bitcoin is able to survive, even the demand continues to increase, this is because Bitcoin has a privilege over fiat. Besides Bitcoin
having a limited supply and higher demand, Bitcoin also cannot be controlled by anyone, that's a strong reason why Bitcoin is very valuable.
Because many people want to do financial transactions without a third party, and Bitcoin can provide that.