Well maybe The Facebook guys were not only after speed optimization, but memory too. No matter how great the LLVM JIT is it probably uses some memory to compile

Well maybe The Facebook guys were not only after speed optimization, but memory too. No matter how great the LLVM JIT is it probably uses some memory to compile the code, and this way wasting some amount. Static compilation would not waste this amount. I'm actually proponent of JIT, over static compilation, but only for my little pet projects. I don't know much about WEB, but for games development, static compilation is sometimes the only way to go (or script interpretation). Sometimes there is just not enough memory, and sometimes it's restricted (hell, it so much resticted that you can't change the VTABLE at runtime in C++ class even if you want to)