Generating C is much simpler than LLVM IR (and you can do structured code generation for C: generate and serialize C AST); it's infinitely easier to read and debug; it allows switching compiler; it provides C stdlib to piggyback on with very little overhead.

It's a fine strategy to start with, there are more important things than fucking around with LLVM IR at this point, they can switch to LLVM or a native generator if they get the thing effective and off-the ground.