Yes, for very sentitive situations/activities where anonymity is of the utmost importance.
Qubes is freaking awesome, but I still recommend a 2nd brand new device that has never been associated with your actual identity in any way, including having never logged in from your home network.
This is way overkill for most threat models. For the overwhelming majority of people, Qubes offers more than enough security via isolation and compartmentalization, including the ability to virtually airgap VMs, anti-evil maid, and anonymity via its Whonix integration and so much more--it's leaps and bounds over any other daily driver OS.
However, if you are performing extremely sensitive activities or are in extremely sensitive situations and you must use technology, and the likelihood of hardware forensics is in your threat model, then I recommend taking the isolation and compartmentalization to another level by using a completely separate device with an OS like Tails.
There is still the risk of having that 2nd device in your posession, so this is where an OS like Tails shines since it leaves no trace on the computer when shut down.
