Another disadvantage is the performance hit you get running in a VM, and in this case, running 2 VMS, even if the Linux distro is more lightweight. Last time I tried Whonix, when it was called TorBOX, it was using Fluxbox or Openbox as the DE, but the screenshots on the web site show KDE now. Is it using KDE now? Because that's the most bloated desktop environment. I'm wondering why they would switch to that for a VM. Other than that, everything you said is spot on.