Can you clarify 'hugely important'? The cited article seems to be saying 'don't make bad design choices or sacrifice usability or accessibility in the name of (bad) design'. I don't see it saying anything about selling more widgets by changing the font.
No, the article tells you that aesthetics have impact on (perceived) usability, fonts are hugely important to aesthetics. Better usability is whats going to sell more widgets.
But in terms of sales the branding is probably even more important, brands are hugely important in selling products, and fonts/typography are a big part of that. I did not focus on that as the article made the aesthetics-do-not-serve-purpose claim, but for sales branding is as relevant if not more relevant.
So if you are selling things I think you can pretty easily justify nice fonts to make your brand and products more desirable.
It does matter what your brand is of course, if your USP is cheap no frills a system font might serve that well.
