Only from my view, once it's automatically parsed, nobody is going to look at it, because either it'll automatically throw it out from the parsed data (in which case a blank resume is an obvious throw away), or it'll do some keyword parsing and determine you haven't copy/pasted enough. The second one is a problem with all of those systems though. After that point it'll pass it on to the hiring manager, at which point they'll look at it regardless of format. PDF then is simply not the best choice if it gives the highest chance of failure at the first step. A Word document is a much better choice.
It really truly isn't. Anyone on any device can reliably open a PDF. That is not true for Word files.
Funny enough, this thread made me want to look at my old resumes. I have a .doc resume from 2009. You know what happens when I double-click it? Nothing. I don't have anything that can view it! Windows 10 doesn't come with a preview tool for doc files. Chrome/Firefox can't preview it either.
I feel you're missing my point here. A PDF is bad for the specific case of inputting a resumé into an applicant tracking system, due to the myriad of things that could go wrong without notifying the applicant of any error, discarding their application without a second glance by a human. A Word document makes the likelihood of system discard due to error much smaller. A docx file is just a zipped file, which contains a document.xml that can be easily read by any regular text editor. It's got all the style information in it, but it's at least more easily computer parseable than a PDF. A doc file is also just a zipped file, with a WordDocument file inside. It can also be read by any regular text editor, but it's got some binary garbage around it. Still more easily parseable than a PDF.
It's the only way to reasonably guarantee someone will be able to open and read a resume in its intended form.