Doesn't Sound Like You Really Know PDF
Firstly who gives a rats behind what sort of PDF format MJNA used for the earnings report. It's not bizzare, it's merely how the individual chose to format it.
Secondly, the earnings PDF appears to be an eFax or scan from a copier instead of being create by saving as a PDF in Word or even saving as a PDF in the print window of Excel. When documents are scanned from a copier into email, the scans come through as somewhat large PDFs. eFaxes are similar larger sized PDFs.
Thirdly, creating a PDF doesn't necessarily mean the file size would be huge even if there are images, simply "save as reduced file" in Acrobat Pro. It's been a while since I've done it, but back in the day when I was a production supervisor/coordinator I easily reduced storyboards, wardrobe references, scripts, prepro books and such that went from 100mb+ to 2-3mb. There is also 3rd party PDF compression software. The smaller size makes it easier to email.
But seriously, who cares? MJNA actually got earnings out in time, that's far more important than the file format or slight slant.