The transparent rectangles in the downloadable SVGs are for sizing. When people used apps like Sketch to create mockups, the SVGs weren't sizing properly because Sketch had no way to understand that there needed to be some space around the icon.
FYI all modern browsers support SVGs and SVG icons have much fewer problems than icon fonts (especially when it comes to fallbacks when the font fails to load).
Totally. I generally use svg icons for anything where I don't need them to match color/size of text, automatically. I just noticed a few people asking for them as a font, and thought I'd help out.
I would be fairly straightforward to use these in icomoon, but for some reason all of the icons have a hitzone rectangle that blocks usage:
I got rid of all those, and made this icon-font, if you want that: http://clarity-font.bitballoon.com/