I studied an art called To-Shin Do for several years. It is basically an evolution of ninjutsu into the modern world. I'd say it's got three big advantages:
1) Flexibility. There are multiple techniques for every situation. Techniques range from rock-hard blocking motions to whirling airy-fairy throws that look like ballet. It uses bare hands, knives, sticks of every length, chains, and improvised weapons of all descriptions. Strikes, blocks, dodges, joint locks, nerve jabs, it's all good.
2) Economy. Every movement of every technique is designed to get the greatest benefit for the least energy. You don't see people doing this art on TV because it's not flashy or photogenic. Properly executed, it can look like almost nothing happened. Suddenly the attacker is on the floor with a broken wrist and nobody knows quite what you did.
3) Brutality. This is not a tournament form. There are no points, no forbidden moves, just pure self-defense. Someone attacks you, you don't think about what's fair, you just put him down. Fair is you win.
For fake martial arts I have to go with the styles of DBZ. Any art where you can throw fireballs, fly, or get bigger muscles by yelling is too cool to pass up.