Because sometimes people don't know C, and because sometimes Windows is a pain in the ass to develop on.
http://kb.sized.io/Right now, it can only build firmware for the Teensy 2.0 and doesn't include sophisticated FN key or LED support, but it definitely has enough features for a first time DIY builder!
I plan on adding more features in the future if people find this tool useful, but try it out and let me know what you think!