Well, you can use whatever semantic tricks you want, but off of certain arrangements of atoms people can live. Off off others they cannot. A certain systems(banking) are designed to return people arrangements of atoms they can live off of. Others(crypto) are not. You cannot change reality via language.
PoS coins have no creation cost. so those would actually follow your idea that its just a number..
but PoW coins actually have a cost that comes with its creation. and due to other features and benefits, they have utility too
fiat does not have the 'borrowers liability/security' you think it does. you are owed nothing when you hold a bank note
bank notes value does not come from its creation. but from someone else working to then give it value after creation in exchange for goods.
thus a simple medium of exchange with no underlying backing
bitcoin has underlying backing right from its creation, which is then strengthened by the work work to reconfirm it each time it is spent. and also the features and benefits once it is being used.