I used it when I worked as a hiring manager. For this task it is ideal. All the behavioral security measures, like only to open attachments from people you trust, break down when your job description is basically to figure out who you can trust.
Qubes comes with a "Convert to trusted PDF" out of the box. Joanna Rutkowska explained how it works under the hood pretty nicely[1]. The tldr is that it is very thorough. With Qubes it is convenient too.
I used Qubes to open the application mails and their attachments and converted the interesting ones to trusted PDFs which I then forwarded to the relevant people. All further communication was only with the trusted versions.
[1] https://blog.invisiblethings.org/2013/02/21/converting-untru...
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