Money is destructive, period. And plastic.
IMO it would be enough if regulators take action against crypto exchanges. Tax outflows heavily, audit companies located in the EU, track bank transfers received from exchanges outside the EU. Controlling the exit ramps to euros is achievable. People can still trade on IRC or whatever, but the scheme is much less appealing when you don't have easy retail money flowing in to buy those coins.
The EU has no fiscal competence, this is left to the individual states.
I don't think much Bitcoin mining is done in the EU? Much of the EU has the most expensive electricity in the world.
From a fiscal point of view the taxation of cryptocurrencies depends on each nation. Many have already decided, by law, how to tax Bitcoin and cryptocurrencies. For example in Portugal if I'm not mistaken Bitcoin is considered a currency and gains made on currencies are not taxed. In other countries it's considered capital gains. Etc.
None of it is harmonized.
The EU simply doesn't have the authority at the moment when it comes to fiscal matters (it's the same for taxes on cars, gold, jewelry, whatever).
The EU probably can issue a rule banning mining using proof of work in the EU that'd then have to be translated into national laws: but I don't think that'd change anything.
Banning mining in China, however... That one would probably have consequences.
If you don't then what you say make some sense, but the European Union think differently.
The EU ban things all the time.
For example: inefficient vacuum cleaners banned: https://www.bbc.com/news/business-41119355
Light bulbs banned (this didn't originate from the EU, but the EU were early)
High watt hair dryvers banned https://www.telegraph.co.uk/news/worldnews/europe/eu/1106153...
Single use plastic banned https://time.com/5560105/european-union-plastic-ban/
Bonus, Bitcoin makes capital flight and regulatory arbitrage much easier. Hostile governments will pay a large penalty.
So either this is a tide that changes the whole world, or it's going to be harshly confronted. Doesn't matter that Tesla buys n bitcoins, or Microstrategy or whatever.
And I do have money on crypto. Not on bitcoin, not a lot, but that would against my interests too.