They're small and have multiple uses. You can write yourself notes, use them as book marks. But, the reason I'm recommending them for travel is because it's a way to write notes to friends you meet. Whether on a cruise, land tour or just in a hostel traveling on your own. Post It's are a great way to leave a quick note for someone about where your when to meet for an activity.
Yes, there are phones, but I find Post It's are quicker and simpler (lets face it, not everyone is good with technology and many phones today are mini computers). And, they're self sticking!
