As far as criminal activities are concerned countries percieve the impact of crypto to be rather significant. So even if 1% of crypto transactions are related to criminal activities, but 40% of all relevant criminal activities are handled in crypto, it is still a problem. I will not take a stand on wether banning crypto is effective in alleviating that or not, but it can certanly score some political points to be tough on crime and therefore be tough on crypto as well. So yeah, some calculations in banning crypto are related to criminal activities. Though it is certanly not the sole or even the most important consideration
Did you think there's no criminal or money laundering using fiat money? lol, Bitcoin exist since 2008, while criminal or money laundering already exist so long time ago, of course they're using fiat money to do that. You should look at this article [1] where the money laundering using Bitcoin is completely far than using fiat money. Criminal can use Bitcoin as an option, but you need to spesk with the data and fact about how much the Bitcoin usage by criminal rather than talking like you're know everything.
[1]
https://www.linkedin.com/pulse/comparing-money-laundering-cryptocurrencies-fiat-aly-madhavji-%E7%A9%86%E4%BA%9A%E9%9C%96Read my comment again. I´m not making most of the claims you are saying. I´m not claiming that criminal activities with fiat money are not happening. My 1% and 40% are not meant to be taken as a fact but as illustration. To give another example. Most of the guns owned by people are used for totally legal purposes. Yet depending on the country there can be a lot of crimes related to gun violence. This means that for politicains it can be useful to consider restrictions on guns. Of course even with gun ban crime can and will continue with other deadly weapons. Just so you would not misunderstand me again. I am not saying that guns and bitcoins are the same. Example of guns is just a useful example in this case. Even if 1% of gun purchases lead to gun violence of some sort, it can still be enough for countries to consider bans or restrictions. Likewise I am not saying that ban on crypto is a good idea. I am merely stating that it is obviously an argument in the discourse.