That is correct. Assuming you haven’t changed any of that yourself: you’ll observe that fedora-38-dvm is itself an appVM that is based on fedora-38 (a templateVM) and acts as “template for disposable VM” (dispVM) which is a checkbox that is enabled in the settings.
fedora-38 templateVM
|- fedora-38-dvm appVM + template for dispVM
|- sys-usb dispVM
Note: your sys-usb is not called disp1234 because it is called… sys-usb! That makes it a “named disposable VM” which means that every time it is created again after being disposed it will get the same name. That is useful because you can refer to it by name instead of trying to guess if it is going to be disp1234 or disp4567 or any other number each time.
But despite that stable name, every time you restart sys-usb it is disposed of and a new one is created like for any other dispVM.