The interesting thing about quantum computers is that they perform very complex calculations, but the answers that they give are relatively short. For example, one important application of quantum computers is likely to be factoring large numbers. The calculation is very difficult but the answer is just the factors.
A quantum computer would be useless for a task like sorting a large list, though, because the calculation involved in doing such a thing is not much more difficult than printing out the answer.
This makes me think of magic tricks. Stage magicians appear to be able to do all sorts of clever things as long as you the audience member can't see what's going on. For example, they can make people disappear or saw them in half, as long as the real business of doing such is hidden away inside a special box. It is beyond the capability of any magician to saw someone in half in such a way that you can see exactly what's going on, or make something in direct view disappear.
The similarity is quite shallow because in quantum computing things are hidden away for very different reasons than they are hidden away in magic - in magic, things are hidden because what the magician is trying to make you believe is happening isn't really happening. In quantum computing, things are hidden away because they are happening in other universes.