My main interest in old magazines is history and research.
I usually OCR any gaming magazines I downloaded that haven't already been made text-searchable. For this reason, I much prefer PDFs over CBR/CBZ (which can't be OCR'ed). I even converted all the Nintendo Power CBR/CBZ files to PDF so I could search them.
It's one of the reasons I'd love to see all the issues on this site made available on Archive.org, where they can be searched before being downloaded.