Tails with a persistent volume is vulnerable to the same attack, and that's how most people here use it. I think the plan is to flush it down the toilet so there's no trace of even a Tails system image on any storage media in their possession. Somebody said in a thread recently that their thumb drive is so small they can swallow it. So Qubes on a thumb drive is not worse that Tails in that respect, but it's better because of VM isolation (although you have to setup a Tor VM, whereas on Tails you manually have to add bridges).