is there a reason why we're not all using SVGs yet? In a word: hinting. For the same reasons that fonts designed for screen use are hinted, so it can be useful

is there a reason why we're not all using SVGs yet? In a word: hinting. For the same reasons that fonts designed for screen use are hinted, so it can be useful to hint icons that will be displayed at small sizes, and of course using a font format allows that but unfortunately SVG doesn’t. Other practical reasons can include the ability to apply things like CSS shadow effects consistently to both the icon and any label text next to it, and backward compatibility with older IE versions that don’t fully support SVG. Of course there are downsides as well. The use of tiny icons as UI elements tends to create more usability problems than it solves unless the icons are immediately recognisable, yet being restricted to the completely monochrome, flat appearance supported by font formats severely limits how distinctive you can make each icon. You also can’t swap out a highly detailed icon for a simplified version of the same idea at smaller sizes/lower resolutions. The article touches on these points, but SVG only really helps with the first one anyway. So personally I’m a bit of a sceptic about the whole icon fonts idea, but it does have some technical advantages over using SVG icons in the limited niche where the icon font technique applies.