It's a very small universe to assume that only illegal activity is conducted with 10k in currency.

I keep asking for legitimate uses of 10k in cash but the only answer I get is that it’s none of my business. It raises questions.

What if I have a fetish and want to buy some crazy sex swing. I don’t want you to know, I don’t want the bank to know, or the government to know. This is 100% legal and 100% none of your business and I prefer to keep it that way.

But banks or the government don’t get the details of what you buy

Unfortunately that’s what makes it scary, what you’re saying isn’t true. Look up “L3 Processing Data” which is becoming more and more common (which informs the payment provider/bank about exactly what you purchased). AmEx for example is notorious for implementing that.

Furthermore, they don’t need the details. What if I just don’t want the government or bank to even know that I spent $10K at “Smucks Sex Store Co.”?

Anyway, I hope you’re starting to see the importance of privacy and cash. Even if they’re ridiculous and silly to someone else.

Because it _is_ none of your business. But feel free to review the thread, there are plenty of examples why having large cash reserves and transaction may be helpful for a given situation.

The argument for reporting is equivalent to "you have nothing to hide" and privacy. This is another aspect of privacy.