With the ubiquity and speed of the Internet, this is already old news: TCG XYZ Material Monster rulings now match OCG rulings. Tour Guide from the Underworld should now be mostly used in Dark World.
It seems like there is quite a few decks in OCG that do not reach their full potential due to TCG exclusives. Lightsworns and Charge of the Light Brigade, Infernities and Infernity Barrier, X-Sabers and X-saber Darksoul. Now, it is Dark World and Tour Guide from the Underworld.
Tour Guide play in Dark World involves searching for Broww to bounce for Grapha or to XYZ and detach as fuel for Gate of the Dark World. If Tour Guide is available in OCG, I will put 3 into the Dark World deck.