I think the idea is that the upcoming calendar/appointment notification is live and always on the menubar. See example screenshot from their web landing page: https://superpowered.me/static/media/menubar.aaa56b48.png

I'm building a similar calendar notification tool for personal use on Windows so I understand the value of this. Calendar notifications via email and "reminders" on the iPhone are not effective for my workflow and I need something that's always active on my menu bar.