payments/transfers would be both much slower AND much more expensive than via a bank

Not necessarily. You could have a federated system, where only big players like banks participate in larger blockchain, like banks already do with forex and wire transfers and pay ridiculous fees to clearing agencies, and clear out local transfers locally, possibly inside their own smaller and much faster blockchain.

Get framework. It has 6 type-c ports, each of which you can breakout into something like 10 ports with usb hubs.

Just the other day I threw a brick into a car window that had a Z sticker on it. Sue me.