Some people look at the "Golden Chicken Solo Stand Stance" (standing on one leg) as something impractical for real fights, and think that it's something used for looking good in performances only.
However, this stance was actually documented in ancient martial arts manuals, such as Shaolin Staff, Chinese Long Saber, or even unarmed fighting in Essentials of The Fist.
Over the years, I've seen this stance being used in weapons sparring several times. This is one time that I've managed to capture it on the camera during my weekly practice.
Black guy with the Spear swept towards White guy's leg, who promptly jumped back and raised up his leg to avoid getting hit. White guy was using Dual Sabers and ready to land on his foot again to return a cut.
The truth is, you most probably won't begin a face-off with an opponent by standing on one leg. This stance or technique is used when the enemy tries to attack your leg, hence you withdraw that leg to avoid getting hit. This way, you're still in range to counter-attack him back easily.
If you were to shift your entire self backwards to avoid the leg-attack, you will have to step forward again to hit him back. This takes longer time, and will give him the chance to recover his composure to block or even attack you a 2nd time.
In general, do not think of stances are positions that you will adopt to face-off with an enemy. Think of stances as positions that you'd move through during combat.
Ancient Chinese Martial Arts Manuals