Bitcion is a world worldwide cryptocurrency and digital payment system called the first decentralized digital currency,and because it is accepted by vendors and merchants as payment and also used for investment Bitcoin is been regarded as money
Even at the first place, bitcoin is a money because people use it to transact and that is the main purpose of bitcoin is to have a decentralized currency system that will give people more affordable way to transfer money with an extra security that you cannot be traced down by the other people and you don't need to fill some personal information just to use it.