Why would that be necessary? For most people, liquid funds are something that's electronic anyway, and in most countries banks can't run out of customers' electronic money. (Safeguards kick in pretty quickly.)

Most of the talk in this discussion is about personal emergencies, like being locked out of your accounts; not about system-wide bank collapses.

You can be locked out of all your accounts simultaneously by a court order, for one.

There is no one reliable place. You must hedge with diverse custodial and non custodial forms of store of value for best assurance.