Yes they are better, if their ambidextrous. Here's why...most dominant left foot players that are ambidextrous(key word) can use their right foot too. Unless you grew up playing against a left foot player, most players are use to defending right foot players and can predict their dribbling attack. When facing an ambidextrous left foot player, they tend to get juked easier and more often because of the unpredictable leg that will control the ball. I'm basing my knowledge from watching my 8yr. old son play soccer, who is ambidextrous and has had a dominant left foot since the age of 3. An ordinary left foot soccer player whose not ambidextrous, plays just like a right foot player but with his left foot. That does not make him better. His style of play becomes predictable because he's unable to use his right foot as often and as successfully as ambidextrous left foot soccer player can. Basically, any athlete that has equal or somewhat similar control from both sides of their body, obviously has an advantage over one sided athletes that have similar skills and experience. That old saying..."two hands are better than one", kinda sums it up. So "two feet must be better than one" also.
They like to say left handed bowlers are better then right handed bowlers. the real reason for that is there are less left handed bowlers. So the oil on the left side of the lane lasts longer then the right side of the lane. I always thought left handed pool players are better then right handed pool players. In baseball if you look at the batting average of switch hitters. It is always higher when the bat left handed. Because most pitches are right handed so batting lefty the curve ball is less of a problem. My nephew is a 6'5 left handed pitcher. He has 20 no hitters. What does all this mean? I have no idea beats the hell out of me Have plenty of right footed players that are comfortable playing on the left side of the field.
Left footed here. I've been the only left footed player in most teams I've ever been in and when team mates realize I'm left footed, they are in utter shock and disbelief as if they found the holy grail. I don't get it but I had one coach in a U16 team force me to take free kicks with some weird outside the foot method which I could only do successfully once in a while. All that because I was left footed. I'm almost at equal level with my right foot with the exeption of striking. I'm right handed and completely useless with the left had, bat on the right, hockey stick on the left and golf of the right.