As everyone else is saying: ban the points of contact. It's basically going to look like the War On Drugs (ironic, for NL). And likewise, it won't be 100% effective.
All of the following are entirely feasible measures for "banning bitcoin" that are already applied to other things:
- directly ban sales or receipts through normal financial intermediaries (banks etc). Try to wire money to Coinbase and get prosecuted.
- directly ban advertising of cryptocurrency products (problem here is you hit the celebrities, good luck prosecuting Musk in NL)
- directly ban holding or making cryptocurrency transactions. Not very effective, but provides an additional charge that can be made against people who've been prosecuted and had their computers seized for other reasons (e.g. drugs, CP). Incidentally criminalizes paying ransoms!
- use all the anti-CP measures against Bitcoin related sites; put the exchanges and known network nodes on the IWF blocklist.
- put bitcoin related software on AV alert lists (I think this has already happened with miner software because it keeps getting installed by malware)
- add it to the list of things checked in border phone sweeps. I don't think NL does a lot of these, but you occasionally hear about the US doing them. Some countries have also started doing device searches as part of other police searches, e.g. https://www.scotland.police.uk/spa-media/zqxibu3s/cyber-kios... ; combine with the ban on crypto tech and this can be used to prosecute people for having cryptocurrency apps on their phones.
Does anyone else remember the "crypto is a munition" era? It used to be illegal to export actually secure crypto from the US, which meant in practice it was illegal to host it on US-based websites. I'm not sure it's possible to go back to that era, but it's possible to imagine github banning crypto-related apps due to international pressure.