A court in Hamburg last week ruled that
a passenger who doesn't wait for the replacement flight is to be compensated. An Amsterdam-Hamburg flight was cancelled, with the replacement taking place the following day, but the passenger booked other travel to get themselves to Hamburg in time, as they had to be there for work reasons.
I am not aware of similar case law in any other jurisdications. Even in Germany, this is reported as a reversal of the understanding of the regulation.