Apart from these are there any other factors affecting it's special nature
As for me it's because of its acceptability, if you ever come across any services that accepts crypto as a payment method Bitcoin must always be present there and again it's decentralization unlike some other coins that can be controlled and manipulate by dev team Bitcoin cannot be controlled, although some think that whales have the ability to do that but that's not entirely true all they can do is to try and affect the market price to a little extent but not Bitcoin itself. But I'm the case of most other tokens or coins the dev of the project have the ability to dump the price completely and making it useless for HODLers.