Think of a performance of a symphony by an orchestra. In the classical computing sense, you would take a single instrument and use it play one note at a time and record it. Then you would play a 2nd note from another instrument and so on. And then you have to put it all together for the symphony to perform.  In the quantum world, you actually have all the instruments of the orchestra playing together, in synchrony. So the different components interfere and amplify with each other and can flow in a single essence. This allows you to perform the orchestra much faster (speed-up) with better quality & allows you to use more complex and intricate instruments. (i.e. deal with more complex problems).  The ‘quantum orchestra’ also has a completely different basis for the composition of the music and includes a much greater scale and variety of instruments. Enabling the creation of sounds that are unique and impossible to achieve in other ways.