No... well... kinda.

The thing you omitted in the article (near as I could tell) is that screens -- especially non-retina/hdr ones -- lack the pixel density to render sans-serif fonts clearly at comfortable font-size for flow content. It's one of the problems here on medium is flow content in articles (paragraphs and the like) are in a serif font that tells large swaths of users to go plow themselves. Which is why I use stylus to override the default font-family here on Medium.

Lacking high pixel per inch density there aren't enough pixels to clearly render serifs. This results in poorly formed glyphs, things blurring together on crappy font-renderer's like Apple's, and in general flipping the bird at legibility.

You can sometimes get away with it in headings, but for most of the content of a website using serif fonts is for all intents and purposes an accessibility violation. Just like in the old days how if you used serif fonts on a 72 or even 150 dpi dot matrix printer it was illegible garbage.

Say it with me: Serif is for print, sans is for screen. Mix the two at your own peril.