because crypto coin bitcoins have very high value, and bitcoin is the first crypto coin that was already popular, the existence of the altcoin is only to cover the limited supply of bitcoin, so until now there will be no coins that can rival the price of bitcoin, so it's not wrong if bitcoin is king of crypto.
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,and Bitcoin is not regulated by any government so while performing transactions,people do not need to have middleman like a bank for performing transactions.