Maybe because the horizontal lines make it easier to read?

**Serif** is the best experience (for most people) for long form reading:

Articles, Book chapters, ...

**Sans** is great for shorter, more chopped up types of reading:

Posts, Wiki entries (with all the links etc...), Descriptions, ....

Many are critiquing Serif as inheritance from the printing press and so on.

Plus, a lot of research has gone into maximizing readability.

Lexend — Change the way the world reads. to name just one example.

But you don't see many customers actually preferring those fonts. Readability isn't everything. Serif has a great vibe going for it and fonts like "Lora" are very much readable enough.

Left: Inter + Lora VS Right: Lexend