As I recall, the hotel packages do not include a transfer from the airport to the hotel but do include a transfer from the hotel to the ship. And this might vary by location.
In general, the hotel packages are not a good value because they are priced per person, whereas most hotels are priced per room.
As always, you need to read the fine print very carefully to see what is included and what is not when you book a hotel through Celebrity, and also what are the cancellation policies.