The hardware overhead to implement this particular instructions is likely very small. The floating operation themselves are done in fixed point with large regi

The hardware overhead to implement this particular instructions is likely very small. The floating operation themselves are done in fixed point with large registers. This instructions tells the cpu to bypass part of the circuit. The javascript thing is just branding to make devs aware of the application of the instructions. Ironically, this actually gives more control of the hardware rather than increase abstraction.