The idea is that we don't need anything other than our phones. It's a camera, recorder, music player, audio reader and there's an app store full of note-taking software loaded with added extras.
I was going to anthropomorphise my phone that it hates me having a life but it's me letting the candy-coloured apps distract me from the people around me and work.
I can leave my phone behind for a lot of reasons but I take a lot of notes while I'm out and about so I treated myself to a cover for my tiny notebooks.