Earlier quoted context omitted.
Bitcoin needs more security than credit cards because transactions are irreversible. Say his mother has a significant part of her savings in BTC, and they get stolen. What's she gonna do then?
Cash needs more security than credit cards because transactions are irreversible. Say his mother has a significant part of her savings in cash, and they get stolen. What's she gonna do then? Answer: let a bank deal with it. Banks can be insured.
Even the dollars a bank has uninvested, they are stored electronically, and it's very easy to undo electronic transactions. Plus, the limiting factor on stealing electronic money from banks is finding a stool pigeon who will do it with cash.[1]
With a system where transactions cannot be undone, you need life-or-death-level security on the entire holdings. No insurance company is going to underwrite a policy of "there is a completely unknown chance of 100% loss."
[1] A PDF of this was on HN recently but apparently I did not bookmark it. Help a brother out?