2000 Yen notes are very common in Naha (Okinawa).
There is no train service (apart from the monorail) and bus services aren't the greatest.
So those who do not have cars tend to use taxis.
As the "average" journey costs more than 1000 and less than 2000 yens, they are widely used in Okinawa.
You can even see on the bank note that the Shuri Castle in Naha is featured as part of the design.