I don't know where you're getting "unnecessary flair" from. What unnecessary flair do fonts like Times New Roman or Baskerville or Bodoni have? (Obviously I'm comparing with other similar fonts traditionally used for body text typesetting with equations.)

I'm talking about good sense of aesthetic proportion and balance, not "flair".

And what exactly is the horrible user experience that Google has created with Roboto, or Apple with San Francisco, or Microsoft with Calibri? They're actually quite excellently balanced and pleasing fonts for their purposes.