This makes a lot of sense. LLVM byte code is pretty damn portable. It just makes a lot more sense since you can maintain PPC/x64/ARMv8 support of a binary file. Yet have native performance in all environments.
What I'd consider more likely is on install you compile to native for both High Power/Low Power chips. It might get funky from an OS standpoint but theoretically you could dyanmically switch between binaries if they were compiled to do that. Its really just dynamic dispatch in Kernel Space.