Mistrust of banks' ability to honour withdrawal requests is largely irrational in a developed country given the existence of government-backed deposit insurance (and the much greater risk of having your cash stolen). I'd actually consider this to be the classic example of irrational mistrust based on a limited understanding of who actually loses out as a result of bank failures, and overconfidence in one's ability to keep hold of their cash.

The inconvenience argument might be true for some[1] people in some countries but is a complete non-starter in my country where retail bank accounts with a positive balance usually are usually fee-free, as are most forms of transfer between domestic bank accounts, most debit card payments and cash withdrawals from most ATMs. It's hideously inconvenient not to take advantage of all that ([1] I understand that somewhere like the US depositors' costs from basic use of the banking system might sometimes be even higher than those levied by non-bank financial service providers they use instead...)

Granted, the moral conflicts argument has a bit more standing, but arguably only if you apply the same standard of scrutiny to other entities you choose to purchase goods and services from (most of whom will deposit your payment in a bank account...). It's not like there aren't banking service providers that have at least seen the marketing benefits of an ethical stance