Convenience is a place to put some shared bespoke plugin functionality that's not necessary to keep in the core.
I know "collecting functionality" might, perhaps, sort of, maybe go against what bespoke might have been meant to be. But whatever.
Convenient prefixes error, event and log messages with your plugin name. Mostly.
It's not like this is an advanced library - I just wanted to move some stuff away from other plugin code.
That's it, really. I was bored, and wanted to create a bespoke.js plugin. Enjoy!