As you point out, there are two variables here: Is it processed in LaTeX, or processed in something else, such as Word? And is the font Computer Modern, or something else, such as Times New Roman?

I think the renderer has much more to do with the readability of a paper than the font. The combination of LaTeX and Computer Modern is certainly pervasive, but if I had to pick one variable, I would rather read papers using a different font but rendered in LaTeX, rather than a paper using a different renderer to lay out a Computer Modern font. For an example of the latter, take a look at this paper, rendered in Word, with Computer Modern font and some LaTeX-based margins and spacings:

https://www.ticoneva.com/journal_files/DefaultLateX.pdf