I'll trust whoever I want, and that includes the FDIC insured banking system. This is an incorrect use of the term "should" which implies obligation. I have zero obligation to go through life without trusting anyone, because I consider that a worse life than one where I make calculated decisions about who I believe to be trustworthy, as all sane adult humans do.

I imagine your alternative is some cryptocurrency that becomes worthless as soon as people stop running the nodes. Yeah, that definitely has less risk than a legal financial entity backed by the United States Government.

My alternative is not some cryptocurrency. I would be happy if credit cards moved to a system where I get a message requesting a charge and I reply to authorize it. Also cash is pretty much a push system, you hand the money to the store instead of telling them where your pocket is and letting them pick what they need. Unfortunately that doesn't work online.