[nextaccountic]

Fiat already has self custody, it's called storing banknotes under your mattress (this is sometimes done in countries with poor bank records btw). The trouble is that you need to cover yourself any risks, like losing the money to robbery or fires

Which incidentally is the same problem of cryptocurrencies: you need to have good security practices to not lose money to malware or simply forgetting the password

When you choose a bank you also have risks, but a different set of risks. It's more like systemic risks, that everyone else would also be affected