1. Having not just all your data with you on a single device, but having *running apps* using that data that can migrate to and from larger screens. Often I dock so I can expand an app I'm already using right then to the larger screen. Handy for multi-tab web research and email.
2. Keeping a laptop w/ you at all times when traveling is a pain. It's easy to keep a phone w/ you. When I travel again, I can safely leave my laptop dock behind in a hotel room. If someone steals it while it's unattended I'm also out much less money than with a laptop.
@kyle this last one is exactly what I was thinking. Docks are cheap. Work already provides USB-C docks. I could easily stash docks at any location I frequent, and have no need of bringing my Linux laptop everywhere I go if I already have a Linux computer in my pocket. I’ve also got reliable and secure network access to my most powerful resources at home no matter where I am, so even if the Librem 5 lacks the power I can have it trigger actions on stronger hardware.