What happens when you set “font_size”: 32 in your favorite editor? I would’ve told you anyway, but I’m glad that you asked.
Wow, all the ideas of the author are bad.
Font size in pixels are a bad idea, because people have different screen resolutions. For some your text might be legible and for some it will be a text for ants. You don’t want that. Also a piece of paper doesn’t have pixels, so you’ll get different results for printed pages. You don’t want that as well.
And the line height thing? No. Just no. Only because I have one larger letter anywhere in my text I don’t want to screw up the line spacing for the whole paragraph/text.
Text size in px is objectively a bad idea.
Font size is definitely not useless. The article assumes that it is, because not all displays are the same size or have identical ppi. However, you are meant to calibrate your scaling settings for typography so that a size 32 font will look identical in any calibrated display or on printed paper.
If you don’t care about printed typography, you don’t need to bother with any of that.
