We chose to get passports for the reasons stated above: getting the kids a photo ID, and for the JIC of cruising internationally. We also live near a border, and discovered we like to cruise, so we do have more than a one-time use for them. For us it was an easy choice. It also made sense on our first ever cruise since it all rolled into the cost/budget for it, including DHs and my passport. What's a few extra hundred, after paying thousands for cruise, hotel, airfare and DSC? I even had to go through the trouble of visiting a consulate and getting my country of citizenship's ID first. Although I probably would have been fine with just my green card, we hoped in 10 years we would have another opportunity to travel internationally.