Fiora is a perfect case of a strategically worthless champion working anyways.
There is, frankly, no real reason to pick her in champion select. These reasons have been expounded upon time and time again, but re-iterate the important ones here:
1. No CC
2. Mediocre burst without ult.
3. Difficult to use sustained damage from Burst of Speed.
4. Easy to build against (Ninja Tabi, Doran's Shield, Chainvest, ect.)
However, we see that she consistently wins roughly 52% of the time. What does that mean? Fiora wins more games then she loses. Why is this?
Franky, Fiora is incredibly gifted at murdering anyone squishy. Zed and Kha'zix are good at this as well, but Fiora is much, much easier to pull off. Let's be honest, none of us are Faker. You are more able to pull off Fiora than Zed. Her top laning and jungle are both horribly mediocre, but because of how incredibly simple she is to play (combined with her high damage output) she is effective in teamfights.
Fiora is a horrible, horrible champion who works because she's incredibly easy to play and provides high damage (the two things you want in solo que).