Comment APIs & Lua (Score 1) 641
The most important reason-feature to learn and use C is that it's the LOWEST COMMON DENOMINATOR in many other languages' attempts for interoperability. These APIs are many times written in C in order for the libraries to operate seamlessly between them. Another good reason is to improve what you can do with Lua. With C and Lua you can literally tact almost any problem, from drivers to databases. It might not be the most efficient way, but definitely you will get more bang for your time and money.