Centimetre, and after the next big earthquake are all numbers off, sometimes even by several meters. Now what you do? New addresses for all, or wrong numbers to new buildings?
When the ambulance arrives wave your hands and say "over here!". So they can do the "last several meters" of navigation by homing on your visual presence.
In the best case your GPS is off by far more than the worst case GPS. There are GPS receivers that can get you to within 2cm, but they cost thousands of dollars and are not used in phones.
In the context of navigation that is good enough - if you are within 100 meters you can look to see your destination.
