Sorry, literally just started checking forums for games I run.

Passwords are banned in the current most popular category because they allow you to make a Level 1 Yokai the same level that an end game Yo-kai is. It takes most of the fun and challenge out of the game by allowing you to just steamroll the entire game.

If anybody ever checks this and wonders why the other restrictions are there: QR Codes are similar in that they allow you to get an abundance of tokens, meaning there would be an early reset point where you run to the crank-a-kai and try to get an S Rank Yo-kai like Damona or something and reset if it doesn't happen.

Saving and Quitting is not allowed for two reasons - they allow you to use the Yo-kai Cam exploit for infinite Holy Exporbs and it screws up the in game time.