Why Add Half of Steady State?
Just to throw another bit of confusion into the mix, as a retired military test pilot and current glider flight instructor, I can confirm something that you will all appreciate: that a headwind reduces your geographic glide ratio. To compensate for this effect when on a glider cross-country, the rule of thumb is that for "most gliders" adding about half the steady-state wind to the no-wind speed for best aerodynamic glide ratio gives close to the best geographic glide ratio when fighting a headwind. Who cares about this when you have engines to get you there? No one really, but when the dust settles, having the extra knots of half the headwind may actually give you the lowest fuel burn for the full final approach (power setting is higher, but you spend less time driving). Of course, this is just conjecture on my part.