> Why not go a bit further - the most secure device is the one you can't use to do anything at all.

That's not far off a reasonable criticism of Purism's security model, that a device so wholly compromised it requires one to activate all physical kill switches to disable the hardware in order to so much as safely enter one's device PIN (per Purism's own site content), that it's no longer useful.

Everyone has to make their own trade-offs, but for me that's a model so questionable that its utility value rapidly approaches zero.