It all started when I saw the latest version of Font Awesome (the icon font I use, love, and recommend) and realized that of 40 new icons, 13 were brand icons, and most of them are, to be fair, useless. Who needs an icon for Leanpub? Or Shirtsinbulk, whatever that is?
If you’re using Google Fonts to improve your website appearance, your visitors are always forced to download the initial CSS file describing fonts from Google’s servers every time they load a page, even though requests to the actual fonts may be cached. This can make your site slower. There are benefits to serving fonts from Google’s servers (for example, Google sends differently hinted fonts for Windows and OS X to improve their readability), however if you want to avoid depending on Google, or to improve load times, you may want to host the fonts yourself.