No it isn't.
It's still gold and fiat.
But it would be because bitcoin is new.
It has been popular nowadays
and there are lots of supporters
So someday it would have the potential to become strong.
Bitcoin is growing and developing today. Although not yet very strong but I myself am very confident that bitcoin has a bright future and will be a strong currency. Because of the potential bitcoin there is. You can see the euphoria of new users
I think it is growing but not developing. And I think bitcoin is one of the strongest digital currency I know, if you think of it, bitcoin is not that of a good digital cuurency, there are many coins that can overcome bitcoin in terms of features, but bitcoin is the first, so I think it is the strongest digital currency.
What makes you think that bitcoin is only growing (in terms of adoption) and not developing in (terms of technology)? If you follow bitcoins github, you can see lots of commit and proposal in there, recently bitcoin had its RSK, (smart contract) and there are lots of proposal about scaling. Is not this development? Bitcoin maybe not the strongest currency in the world but it is the strongest decentralized digital currency in the world.