They will need crew available for when they attempt to move the ship in the near future, also there will have been maintenance services to carry out in the weeks since the collision.
They are hoping to arrange limited shore leave once the ship has been moved to a safer position.
They have been given basic phones, so can make calls, but they don't have family photos for example. It's understandable that the authorities would want to know what the crew messages were immediately before and after the collision.
There are going to be lengthy legal battles in the not too distant future.