Why is fingering important

A very important aspect of piano playing that is often overlooked is fingering.  When learning a new piece of music, one of the main issues with using the right fingering is that to the ear, the wrong fingering sounds exactly the same in terms of note and rhythm. What I often tell students is that "when it's slow, anything goes"; for example, you can simply play a C-major scale with 1-2-1-2-1-2-1 fingering at a slow tempo and it would work just fine.

The problem becomes more noticeable when the tempo increases, as the execution with a bad fingering becomes more noticeable. And if one tries to fix the fingering at that point, then one will be battling with "incorrect muscle memory". Obviously one can still try to correct the fingering mistake, but it will become a more difficult task because the finger(s) are comfortable with the wrong fingering. To  the muscles, playing a wrong fingering is just as big a mistake as playing the wrong rhythm or wrong note!

So the solution to this is quite simple: SLOW DOWN when you're learning a new piece so that your brain can observe the fingering along with the notes and rhythms. This can actually save you time at the end!