Sans fonts lack the serif features of a typeface, and may be better suited for casual sites. They go a long way in giving an updated look.
The early websites on the internet were dominated by Times New Roman. CSS was barely a thing, and a majority of people making websites weren’t specifying a font.
With a simple change of specifying a font, you can make your website look like it wasn’t just made in Notepad.
Examples
Personal websites with an extremely minimal and clean look.
- paulgraham.com — you might see the purple sidebar and think this website uses color tags. It does not. The sidebar is actually an image.
- patrickcollison.com