Personally I haven’t tried to use it as disposable, however I don’t think it’s impossible to do so.
You just need to make a sys-usb-like qube. Since there’s no VM name changes in this process, perhaps you don’t need to care about policies.
Remeber to make those autostart config persistent.
I put 500MB on it, just arbitrary.
I didn’t modify my soundcard in sys-audio. Just a conf in modprobe.d to avoid the scratchy sound issue.
Ref: Setting up an audio VM - #23 by alte and Setting up an audio VM - #15 by kef