The biggest attributed contribution of Bitcoin is Being a game-changer and changes the world.

Without Bitcoin appearance in 2009 and its contribution, we might not have the crypto market as big as nowadays (of course, it's still smaller than other markets) and the blockchain technology would have yet appeared or have yet achieved what it has now.

For technical aspects, I think we can skip them here. Simply said, Bitcoin changed the world, from individual to governmental, national aspects.