The Point Of This Flight
What was the point of the flight? It was basically to show that the firm can take us to the International Space Station. The plan was to send a spacecraft to orbit Earth before it docked at the station. It is also very important for the Crew Dragon to show that it can bring the passengers back to terra firma safely.
NASA Commercial Crew Program
You might have already inferred from the test alone that this was the second test flight for the Crew Dragon. The first one did not have actual people on board, so this was a huge milestone. Its launch was part of the bigger objective to get certified under the NASA Commercial Crew Program. This was important as it would allow more trips to the International Space Station in the future.