If you deposit your money at a bank, or PayPal, or some online digital bank transfer service,** you do not have your money anymore.** They have your money.
Now you have some kind of contract that says they'll give you your money on demand. But sometimes they won't give it to you when you want it. If any judge or cop wants to see every person or business I've ever transacted with the bank will happily give it over.
On the other hand, cash is cash. If I possess it, then I have it. And nobody gets to know how much, or how suspicious, or with whom I'm transacting.