If you get in a fight with someone who is smaller, weaker, and slower than you, then your natural advantages will almost always defeat such an opponent without any training necessary. Therefore, if you are going to learn a self-defense style, shouldn't it specifically train you to defeat opponent(s) who are bigger, stronger, and faster than you? Wing Chun is the only martial arts system known to be invented by a woman (the "weaker" gender), and was specifically designed to defeat bigger, stronger, faster, and multiple opponents with or without weapons simultaneously.
Most Traditional Martial Arts (TMA) like Taekwondo, Karate or Capoeira are overly flashy and acrobatic slaving to outdated and unusable forms constantly drilling impractical techniques that are not effective on the street. The current trend of UFC (Ultimate Fighting Championship), MMA (Mixed Martial Arts), and grappling styles like Jiu Jitsu, Judo, and Wrestling, has many people convinced that the pinnacle of effective self-defense is one or a combination of these hard-form, one-on-one fighting styles. While these styles are indeed formidable and have proven themselves in the ring, consider, in real-life when faced with the necessity to fight:
1) You often must defeat multiple attackers simultaneously
In UFC, MMA, and cage fights as well as TMA tournaments, the fighting itself, and thus the bulk of your training, is geared towards one-on-one confrontations of 2 or 3 minute rounds. In real-life however, the average fight lasts a mere 9 seconds, and often includes multiple attackers. Thus the dominance and perceived effectiveness of hard-form/grappling/UFC/MMA etc. is only valid in one-on-one fights when you can afford to spend minutes rolling around on the ground with your opponent trying to get a limb-lock or strangle-hold. In a real fight with multiple attackers, while you're busy rolling around wrestling one guy on the ground, his buddies are all standing straight kicking the snot out of you.
2) Those attackers are often bigger, stronger, and faster than you
These competition fights are always pre-arranged so to only match two fighters with comparable skills and attributes. This means that these fighters are always training to defeat their mirror-image. In real-life scenarios, however, your opponent(s) will often be bigger, stronger, and faster than you, and only the soft-form martial arts are specifically designed to combat this. Wing Chun is a combination hard/soft style which employs simultaneous attack and defense, yields to all incoming pressure, and diverts it away from your center-line while simultaneously attacking the opponent's center-line. This advantage allows even novice Wing Chun practitioners to defeat opponents twice their size, strength, and speed.
3) Those attackers often have weapons
Another issue that every martial artist must consider is self-defense against weapons. In tournament fighting styles, the bulk of your training is devoted to one-on-one, empty-hand combat. If any self-defense against weapons is taught, it is usually minimal, difficult to develop, and quite ineffective in real-life. Wing Chun's movements and concepts, however, are so universally applicable to any fight situation, that empty-hand practice, weapons practice, and empty vs. weapons practice all utilize exactly the same training techniques. This means regardless of the fight situation, you are poised and prepared with muscle-memory to react more effectively to any empty-hand or weapon attack, because all of your training is universally applicable regardless of how many attackers, how strong they are, or which weapons they have.
4) There are no rules, referees, or tap-outs
In all tournament fights there are regulations, referees, points, tap-out or knock-down rules, but in real-life fighting there is no such thing. This means if your martial art caters to tournament fighting, as most do, then your training is not comprehensive, not utilizing every weapon available to you. For example, Taekwondo has no punches to the head or in-fighting techniques. Judo, Aikido, and Wrestling have almost no striking whatsoever. Even UFC and most MMA fighters train with rules in mind like no groin strikes, no eye gauges, no knee stomp-kicks, etc. This may seem insignificant, but consider that the two most vulnerable spots on the human body are the eyes and groin. This means that most tournament fighters are merely training for unrealistic sparring situations in which they cannot even attack their opponent's two most vulnerable targets! Wing Chun on the other hand is not a tournament style, and practitioners always train to attack their opponent's most vulnerable targets like eyes, groin, throat, elbow and knee joints.
Most fighting styles (such as Boxing, Kick-boxing, Wrestling, Karate, Taekwondo, Muay Thai, Capoeira, etc.) rely on speed, strength, and vigor to overcome an opponent, so unfortunately as you grow older, your effectiveness in using the fighting system diminishes. Wing Chun, however, relies more on philosophy, sensitivity, intuition, and other internal factors which you will continue to improve upon your entire life. Wing Chun is scientific, logical, and concept-based so both your understanding and ability will only increase with age. This is why 80+ year-old Grandmasters like Ip Chun, Jim Fung, and others can still defeat all their students and generate incredible internal energy.