You're confusing electronic or digital money with virtual currency created from nothing.
The role of the central bank in creating money will remain.
Virtual currency created by some phantom guy and controlled by some phantom committee will not replace the modern gov's role in creating and regulating money.
The idea that because it's computational hard to create some crypto key - will somehow make such virtual currency - have some value is crazy.
Gov will remain gov. Gov will remain with guns - and all military might - to decide what is right or wrong.
The rest are details.
Yes virtual currency will have their use cases...like Mombasa's BanglaCash used in Bangladesh Slum.
There is no doubt that money will remain - but coins and notes - will certainly disappear.
The money will continue to be issued by gov controlled body under very strict controls. Be it in cowries shells, gold, notes, electronic money - it won't be bitcoin.
Bitcoin and virtual currenciesies - and their exchanges will exist - at the periphery - mostly for illegal stuff - because gov doesn't like competition in stuff like making money or making weapons.
Bitcoin and crypto currency will become mainstream currency/money. As they say fiat is by consensus. Basically we both agree that the exchange of good with a said amount of Bitcoin is equivalent value.... How else did we trade with salt or courie shells; what was the measure of value?? How did King Sundiata or Mansa Musa know the equivalent value of his gold or salt exchanged?
Printed money as legal tender is a very recent concept. It is time now to move to the next iteration which is digital currency.... Not controlled or under the thumb or influence of any central bank or big brother nation. Its volatility and inflationary nature will stabilize and will become generally accepted as a means of trade.
Soon, when central banks launch their CBDC (Central Bank Digital Currency).... backed by the national legal tender 1:1 or however they designate, digital currency (and subsequently crypto currency) will become ubiquitous. With this ubiquity, it will no longer be any need for central banks to refuse to recognize or accept Bitcoin and Bitcoin will be the gold or bullion reserve currency. As I said earlier the widespread adoption and network effect will see to this being a globally accepted means of exchange.
Lest we forget the Mpesa digital wallet is indeed a digital currency backed 1:1 to Kenya shilling or whatever currency in its market of adoption.
As regards the dark web or the FUD that Bitcoin is for criminal activity, who says that you cannot apply or use the dollar, pound, Swiss franc etc for same activities. The larger amount of these illegal activities have been transacted in these currencies.