It could also act as a button to trigger a set of actions.
There's a lot of room for customization especially if the widgets became interactive with the next OS release, I could have multiple buttons per widget that display some information with real-time updates,...
I could see this having a million use cases, which complements the already amazing BTT!
The next non-alpha BTT release will finally come with the "floating menu feature". These can contain all sort of widgets and can be placed anywhere on your screen. However they will not integrated into the notification center.
Currently implementing optional auto-hiding for these: