[ken]

> There are no guarantees when relying on a system's default fonts, and that's why web fonts are popular.

Technically true but misleading. There are no guarantees when including custom web fonts on a web page, either. It's the web! No matter how much fancy CSS/JS wizardry you throw in there, it's ultimately up to my browser to put the bits on the screen.

I guarantee most web designers didn't test with any of my 3 main web browser configurations, because a good portion of the time I can't even read the text through their CSS.

Earlier, you pondered:

> There seems to be a reply like this at the top of every font-related thread on HN. I often wonder whether it's coming from designer/developers or from end users.

It's amazing how many designers screw up web fonts -- maybe that's why avoiding them is also so popular.