Very good question, thank you for asking! :)
I felt like there was no better name for it, being like a real companion or copilot in every app I use. So I wanted the name to actually reflect that.
In all seriousness though, you could end up being liable for diluting their trademark, and if you aren't set up in a corporation, the liability could hit you personally.
I'm not a lawyer anymore, but this is the sort of thing that sets off all kinds of alarms in my head. This looks like a cool project, and it would be unfortunate if it got mired down in legal controversy — especially if that was totally avoidable.