More importantly, the customers of the cpu vendors use benchmarks to evaluate potential chip suppliers, and Js benchmarks are near the top of the list for ARM n

More importantly, the customers of the cpu vendors use benchmarks to evaluate potential chip suppliers, and Js benchmarks are near the top of the list for ARM now. Everyone from the OS vendor to the compiler authors to ARM itself are looking at the same operations, so instructions like this get requested and added. There are also funny xaflag, axflag instructions in armv8 specifically to speed up x86 emulation on arm64. I believe they were added at the request of the msft emulator team.