The value of Serifs
Whenever I am selecting a font for use in any project, one of the most important things for me is legibility. Sometimes I will use sans serifs if it is more informal or brief, however Serifs tends to be more readable.
This can be demonstrated easily by asking people how they read the.glTF file format. I have seen and heard people call it .gITF which is a result of various sans serifs fonts failing to distinguish l, L, I, i and 1.
This is an issue that makes them indistinguishable. Among the worst occurrences are where you manually, letter by letter copy passwords, keys or URLs and most of the time they are displayed in sans serifs when what the individual character is, can't be intuited from context and has a high amount of importance. Dyslexia friendly fonts focus on exaggerated serifs OR make up for a lack of it in another way with distinct silhouettes.
Even monospaced fonts tend to have serifs as the actual characters in your magical incantations have to be exactly correct.
Note that not all sans serif fonts fail at this. Most... Embarrassingly do. This is my top issue with fonts, just behind bad kerning. It is also probably why it's a default in plain html browsers... Because it's a sensible default.