We loved the passports! I think our girls, 10 and 6, would have been bored with the WS without them. But they had so much fun finding the next kidcot stops. The books come with the various country stamps, we sat down and they actually did all the stamps first. Then as you go country to country, each stop has someone who usually will speak to them at least partly in the country's language and write in that language too. My girls got their names written in Japanese, etc. They will also stamp the masks that they can get too. If we do it again, I think I would have them choose either the mask or the passport because its the same stamps on both and it just made more to carry.
They have already looked back on them here at home and talk about all the countries they visited, so we felt it well worth it and a lot of fun!