I would also suspect that using data collected by governments is used for business advantage. Of course it is hard to prove quite often. Personally I think that in principle it just doesn't make sense to spread your data around, as the benefits are tiny and the potential downsides can be big.
Basically if you were high profile enough, people would watch your wallets to see what you were investing in/transacting with, and use that as market intelligence.
As far back as 2016 or so I recall someone specifically offering their blockchain analysis platform as a way to do this.
So you would use tornado to make the money you planned to invest/use appear "somewhere else" disconnected, to maintain privacy/security of a project.
Tornado and mixers and such become necessary specifically because all transactions are public - unlike in tradfi where transactions are opaque except to parties and intermediaries.
Similarly to how investors in tradfi tend to keep their investment strategies secret where possible.
Scenario two. I want to have on-chain identity (e.g. exo762.eth domain name). To register it I need to have some ETH (gas, registration fee). If I sent this ETH directly from my "money" account, I will forever link my public identity to my money, which is like walking around with "my net worth is at least XYZ USD" banner.
We're in a thread about a rogue state using the tech to steal money to fund their operations (Chemical attacks in airports, nuclear warheads, intercontinental ballistic missiles, etc.) How many nuclear detonations would you consider acceptable in exchange for the cryptobros to have their toys?
https://www.bbc.com/news/stories-57520169
More prosaic wire fraud is common in real estate and B2B transactions, and if not noticed immediately the funds are often lost after being transferred internationally and cashed out. It wouldn't be surprising if NK is behind some of that, given what they managed against Bangladesh.
We've come a long way from Mario Bros!