This first image above shows a scenario that you may be familiar with. The circles represent capabilities, for example access to an email account, access to social media, or a cached files. Alice's work desktop has very different but slightly overlapping capabilities from her personal laptop or phone. Alice's most active device is her phone, and so it has more capabilities than her laptop. We can see that Alice fills many roles across her personal life, work life, and aspects of both. They are all the same human being, but each persona behaves differently and is expected to maintain some degree of separation (e.g. no sensitive documents brought home, or NSFW photos on her work desktop).