The PERF page is used to calculate how much airspeed that the airplane should use when doing the approach (which in turns tells the engine how much thrust it needs to apply or reduce). It calculates the current weight, plus the barometric pressure, temperature, and wind direction and speed.
Generally, if there’s a strong headwind, then the aircraft will calculate a higher approach speed because the airspeed sensor would be registering a higher value than the actual ground speed. So it needs to take that into account to the VLS and VApp calculation.
Without it, then the aircraft would probably approach the runway at less-than-ideal conditions (it could be too fast, or too slow). But as far as the Localiser and Glideslope is concerned, it has nothing to do with it, and it would still capture and follow the signal down to the runway.