It really does not add anything on top of butler, but it just makes it easier to use, without having to add butler to PATH.
I just made it as a tool for people to update their games easier. It has a tutorial in the app to update your game.
Sorry it does not add anything on-top of butler.
If you would like to suggest something, here :)
Also Leafo, thank you for make Itch.IO. You have done a great job here.