I started noticing these about two years ago. They’re really my favorite of all the promotional items companies often give out. I usually put three things in mine- an ID, a metro card, and a credit card. Though individual uses only save me a few seconds each, my quick estimation of the total time I’ve saved using phone wallets is about one hour through hundreds of uses. I don’t think that the value these provide is so much in the time saved as it is in convenience and avoiding the feeling of searching through one’s wallet as a cashier stares and others in line wait. However, one tradeoff for this convenience is likely the security of the contents in the cell phone wallet sticker. The objects are certainly not held as securely as in a typical wallet and are probably more susceptible to theft by being somewhat exposed. For such reason I didn’t use mine while I was traveling across South America. My Argentinian friends told me that the product would never work in Buenos Aires because exposing one’s valuables in such a manner would quickly lead to theft. It’s interesting to me that a product I, among many others, find highly useful may not be seen as desirable in other places.