I've seen more people get jacked of all their cryptocurrency holdings than any significant amount of fiat on their person, due to targeted viruses and backdoored systems. I've also seen numerous occasions where someone sent money to the wrong address and that was it, the money was forever sent into the void.

There was a guy on reddit who had all of his DOGE and BTC lifted right off his computer. He was using strong, auto-generated passwords stored in a password manager, so he was not even typing in passwords that a keylogger could intercept. Presumably the attacker had a backdoor into his system, watched him work, and just transferred out the funds when he wasn't at his desk. Poof - all gone, with more or less proper security measures in place and no clear sign of an intruder other than the missing money. Several other people reported similar events in that thread.

These are still major problems for mass adoption of crypto, completely setting aside the massive cases of fraudulent pools, online wallets, exchanges, etc., etc. There are many subtle problems that are difficult to diagnose and cure that come with a technological solution like bitcoin, that paper money simply does not have.