Because the apps can initiate a call by just pointing a webview at tel:0000. Another reason is hybrid apps, imagine a contact hybrid app running in something li

Because the apps can initiate a call by just pointing a webview at tel:0000. Another reason is hybrid apps, imagine a contact hybrid app running in something like PhoneGap. You want to click a button and call right away without the phone asking you to confirm your action. I'm not saying that Apple's design is good, but it is documented.