I think bitcoin is special because it is control and manage by yourself no third party need to tell you how you should run your investment that is why is called a decentralized platform, secondly bitcoin is the most special coin among other coins in cryptocurrency because of it potential and the row it playing as the first crytpocurrency coin in blockchain technology which make him the king among other coins.
There are many thing which make bitcoin so special. First of all is its decentralised nature because which it doesn't under control of any kind of authority or government and second thing is its market price. It is the first virtual currency which price is higher then gold. This thing make it as a investing tool and also make it special too. Secondly its money transaction facility which also make it special. It provides the uninterrupted and untraceable money transaction facility. And also provide untroubled international money transaction facility. And this thing also make it special too.