Ofc this tool screws over legit players, even if only used it to increase hearts, coins and jewels.
As soon as you have access to extra coins to buy mega starts, disruption delays, complexity, etc that you wouldn't have had without this tool (or submitting to the microtransactions), you're skewing the outcome of all events... Editing your Pokemons stats, and gaining any of the megas, etc, is just skewing it even further... at which point, editing competition scores is moot, because the game is now unfairly broken for everyone.