I could say speed, but the main reason for me is because it is fun. And I like to see what I can make C do. :D
If anything, you've gone further along the "also (at least sort of) practical" scale than I expected.
Given as mentioned elsewhere a per-request arena + bump allocator system, it might actually be -genuinely- practical (to the extent that writing application logic in C is at all ;)
Bravo.