There is another thread in this discussion where we discuss this, pointing out that default fonts in browsers tend to be quite ugly.

See here: https://news.ycombinator.com/item?id=21841011

There’s also layout issues caused when replacing a font with another font, unless the metrics are precisely duplicated. There’s a reason RedHat paid a lot of money to have Liberation Sans with the exact same metrics as Arial, Liberation Serif have the same metrics as Times New Roman, and Liberation Mono have the same metrics as Courier New.