Seems a little drastic if it changes the natures of all Pokémon you encounter for the entire day but still something I will definitely be making use of! I guess I'll probably use it closer to the end of the day to get a specific natured mon before stopping to play or something, since I wouldn't want everything I catch to be forced into it haha. Though it absolutely makes sense from a comboing and shiny hunting perspective...very convenient there.
Will be unlocking the Judge feature very soon too. =')