Most current system screen fonts in major OSs - as a general group, as a set of letter forms - are not and never were printed fonts. They evolved from bitmap fonts that were created with 90s constraints in mind. They retain some of that aesthetic, and they are not usually the best candidate for the job.
Leaving it up to your user's system font is also an arguably poor choice.
> Most current system screen fonts in major OSs - as a general group, as a set of letter forms - are not and never were printed fonts. They evolved from bitmap fonts that were created with 90s constraints in mind. They retain some of that aesthetic, and they are not usually the best candidate for the job.
This couldn't be more wrong. Things have progressed since the '90s.
Apple, Google, Microsoft hired real typographers to create their new fonts. Apple uses San Francisco in their printed materials all the time.
On Apple devices, system-ui is San Francisco, a TrueType variable font with 2937 glyphs, 4 axes and 369 instances. The axes are width, optical size, grade and weight. San Francisco also has all of the goodies someone who cares about typography could want: ligatures, small caps, contextual alternatives, true fractions, etc.
I think this qualifies as "giving a shit". ;-)
BTW, you can see each named instance in the developer tools in Firefox and Chrome on macOS.
An instance is a combination of the 4 axes; the instance of San Francisco compressed thin uses can be specified in CSS as:
Leaving it up to your user's system font is also an arguably poor choice.