C is for system programming, its basically one layer over assembler.
If you know what yo do, you can make it better as in very other language and even faster, except you go for Fortran (don't laugh, there are high speed areas where you still need that).
The times where you coded big applications with C ended long ago - but its still one of the most important languages around.
Beside the whole linux world is based on C - the internet would not really work without it.
You don't want your graphics drivers done in Python, aren't you?
And most people here already use a kind of C, even they did not know - php is nothing more as a syntax ripoff from C.
If you can do php, you can learn C in a few hours.
The object part of php did not change that - thats a ripoff of C++, if you want so.