It's still optional. You don't have to create a sys-usb VM. It's not even created by default if you have a USB keyboard: https://www.qubes-os.org/doc/usb-qubes/#how-to-create-a-usb-.... See also: https://www.qubes-os.org/doc/device-handling-security/#usb-s....

I use the latest version of qubes and sys-usb and I don't ever reassign my usb keyboard(I do for other usb devices.) It sounds like the person from the top comment just configured their system in an annoying way.