Bitcoin isn't really money same way as US dollar isn't really money.
Behind the US Dollar is a whole country and a lot more countries if not the whole world.
Behind Bitcoin are random investors, random people.
Bitcoin is also rarly traded directly it uses fiat for most. So Bitcoin is even dependend on this proof-of-stake system.
Bitcoin is a proof-of-work system dependend on the best proof-of-stake system we have.