It's great. I used it right now as I often have things I need to remember but I can't just dumpt it in my team's Trello. I think you can go ahead and brand it as a light weight Trello for a niche that wants privacy/is lazy and just wants something quick.
LocalStorage can take you miles ahead if you indeed make sure people use this as I described above. I certainly would.
You can create multiple boards in trello, mixing personal and business. This means you can keep all of this stuff in the same system, but not have them appear in your Team's trello.
Isn't that way simpler? That's how i do it anyway.
This is something I would like to provide but whilst keeping it disconnected from a database. Integrating with google drive or the likes is what appeals to me most at the moment.
LocalStorage can take you miles ahead if you indeed make sure people use this as I described above. I certainly would.