Since Bitcoin was created as the first cryptocurrency, it had to fulfill its main role - to be an alternative to the currently existing financial payment system precisely as a means of payment. Therefore, no additional functions were given to it.
Over time, there were many different uses for cryptocurrency, and various altcoins began to perform them. In addition, thanks to the open source code, everyone has the opportunity to create their own cryptocurrency and here it does not do without duplication and useless coins. However, in general, it is altcoins that are rapidly developing the world of cryptocurrency.