I generally agree and don't support a ban, but cryptography is much more generally useful.
To put it another way: cryptography has many legitimate applications for normal people. Cryptocurrency does not yet (and may never, as long as civilization doesn't collapse).
Cryptocurrency, being a currency has its value tied to its utility (e.g. the usual talk about decentralized, private, and resiliency against inflation which have been beaten to death).
This is clearly an existing use for normal people. Whether it will gain wider adoption for everyday payment remains to be seen.
More importantly, it doesn't need the civilization to collapse. In fact if civilization were to collapse ain't nobody gonna validate your transaction!
Lol comparing cryptocurrency with pokémon card is new level of... uh creative but not very bright perspective.
OK let us pretend Pokécard has some crypographically proven properties that makes it useful as currency.
Pokecard as a coin is speculative only when compared with fiat; one coin is one coin and its value stays in term of its utilities.
Regardless, further reading is usually very useful before forming strong opinion.
(1) I would argue speculative assets is a concrete use case which is a pros, it's for capital gain. Anyway, your speculative-as'a cons argument crumbles as soon as stablecoin is mentioned. Stablecoin is pegged to stable fiat.
(2) Deflation and inflation mechanism of cryptocurrency varies differently on each coin. BTC itself inflationary by nature due to its halving mechanism. Other coins may have same or diffrent approach.
By now I hope you would see the benefit of forming informed opinion: there are a lot types of Pokécard—I mean cryptocurrencies, reading few sentence about BTC does not mean it encompasses all cryptocurrency . ;)
Finally, since you are so obsessed with cryptocurrency as a way to subvert govt: it's only one of use case.
Stellar or Cardano (I forget) aims to be backbone for scalable, and cheap payment network, Ethereum is not only a currency, it has smart contract that allows you execute your program. Those has zero thing to do with a working govt or not.
To put it another way: cryptography has many legitimate applications for normal people. Cryptocurrency does not yet (and may never, as long as civilization doesn't collapse).